UC-NRLF 


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MEDICAL    «SCH<S>©L 
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EX  1 1BKIS  ffi 


MEMORIAM 
DR.  JOHN  MARSHALL  WILLIAMS! 


INCLUDING  A  SPECIAL  SECTION  ON  THE 
FUNDAMENTAL  PRINCIPLES  OF  ANATOMY 


EDITED    HY 


W.  T.  ECKLEY,  M.  D. 


I'KOFESSOK    OF    ANATOMY    IN   THE   COLLEGE  OF  PHYSICIANS  AND  SURGEONS,  UNIVERSITY  OF  ILLINOIS ;    PROFESSOR  OF  ANATOMY 
IN   THE    NORTHWESTERN   UNIVERSITY    DENTAL   SCHOOL;    PROFESSOR   OF  ANATOMY   IN   THE   CHICAGO  CLINICAL 
SCHOOL,  AND  DIRECTOR   OF   THE   CHICAGO    SCHOOL  OF  ANATOMY  AND  PHYSIOLOGY;    MEMBER 
OF    THE    AMERICAN    MEDICAL    ASSOCIATION,    THE    CHICAGO    PATHOLOGICAL 
SOCIETY,  THE    CHICAGO    MEDICAL   SOCIETY,  THE    MEDICO- 
LEGAL   SOCIETY   OF   CHICAGO,    ETC. 


AND 

MRS.  CORINNE  BUFORD  ECKLEY 

INSTRUCTOR    IN   ANATOMY    IN   THE    NORTHWESTERN    UNIVERSITY    DENTAL    SCHOOL;    PROFESSOR   OF   ANATOMY    IN   THE 

NORTHWESTERN   UNIVERSITY  WOMAN'S  MEDICAL  SCHOOL;    PROFESSOR  OF  ANATOMY  IN   THE 

CHICAGO    SCHOOL    OF   ANATOMY   AND    PHYSIOLOGY 


WITH  347  ILLUSTRATIONS,  MANY  OF  WHICH  ARE  IN  COLORS 


PHILADELPHIA 

P.   BLAKISTON'S    SON    &   CO. 

1012  WALNUT  STREET 
1899 


COPYRIGHT,  1899,  BY  P.  BLAKISTON'S  SON  &  Co. 


PRESS  OF  WM.  F.  FELL  &  Co., 

!22O-24   SANSOM    ST., 

PHILADELPHIA. 


PREFACE 


We  have  the  honor  of  submitting  this  little  book  as  a  dissecting-room  guide 
to  "  Morris'  Human  Anatomy." 

The  growing  tendency  to  specialize  in  the  practice  of  medicine  has  reacted 
on  the  branch  of  medical  science  that  continges  every  medical  specialty — anatomy  ; 
with  the  result  that  our  schools  are  compelled  to  keep  pace  in  teaching  this 
branch. 

Those  areas  of  the  body  that  can  not,  under  existing  conditions,  be  profitably 
studied  in  the  dissecting-room  are  properly  presented  by  the  lecturer  on  anatomy. 
Thus  the  student  has  the  benefit  of  the  professor's  dissections  and  investigation, 
and  the  additional  opportunity  for  minute,  detailed  dissection  and  study,  which 
he  could  not  enjoy  in  the  dissecting-room,  where  gross  anatomy  is  the  main 
topic.  The  minute  and  descriptive  anatomy  are,  then,  to  be  studied  in  Morris. 

In  this  book  the  gross  anatomy  only  will  be  considered.  For  instance,  the 
contents  of  the  orbit, — as  the  nerves,  vessels,  muscles, — as  found  on  the  cadaver, 
will  be  considered,  but  the  anatomy  of  the  eyeball  will  not  be  taken  up.  The 
gross  anatomy  of  the  peritoneum  and  other  abdominal  contents  will  be  con- 
sidered, while  the  student  will  be  referred  to  Morris  for  the  special  anatomy  of 
each  individual  organ. 

Several  pages  have  been  devoted  to  the  sympathetic  nerve, — which  every 
student  should  thoroughly  dissect, — for  the  purpose  only  of  teaching  the  student 
to  find  on  the  cadaver  the  relation  between  sympathetic  and  their  parent  somatic 
nerves. 

The  method  of  studying  structures  in  the  normal  order  in  which  they  are 
exposed  in  dissection  is  followed,  it  is  believed,  as  nearly  as  it  is  possible  to 
accomplish  this  very  desirable  end. 

To  aid  the  memory  in  fixing  salient  points  seen  in  dissection,  frequent  review 
quizzes  are  given. 

In  the  introductory  chapter  are  certain  rules,  principles,  and  generalizations 
which  underly,  to  greater  or  less  extent,  the  science  of  anatomy.  It  may  be 
urged  that  matters  of  this  nature  are  too  elementary  for  medical  students.  How- 
ever this  may  be,  experience  teaches  that  students,  even  after  having  studied  the 
subject  for  months,  have  a  memory  well  stored  with  anatomical  terms  which  are 
mere  abstract  ideas  ;  they  are  too  often  ignorant  of  the  fundamental  principles 
of  our  nomenclature. 

If  anatomy  is  a  nomenclaturic  science  [Can  any  department  of  learning  be  a 
science  without  a  nomenclature?]  then  certainly  the  place  for  the  student  to 

285  "'6 


iv  PREFA  CE. 

learn  this  nomenclature  is  in  school.  The  practice  ot  assuming  too  much  knowl- 
edge on  the  part  of  the  student  I  believe  to  be  wrong  in  principle.  At  any  rate, 
we  must  remember  that  this  book  is  written,  not  for  those  who  know  anatomy, 
but  for  beginners. 

To  impress  on  the  student  the  necessity  of  tracing  muscles  to  their  exact 
origin  and  insertion,  illustrations  of  bones  having  such  attachments  indicated  in 
color  have  been  introduced.  These  and  nearly  all  other  illustrations  are  from 
the  work  to  which  the  text  most  frequently  refers — "  Morris'  Anatomy."  We 
wish  also  to  express  our  thanks  to  both  author  and  publisher  for  the  use  of  the 
excellent  diagrams  from  Potter's  "  Compend  of  Anatomy,"  and  for  the  many 
illustrations  of  the  muscles  taken  from  Gould's  (Illustrated)  "  Medical  Dic- 
tionary." In  addition  to  these  we  have  contributed  about  sixty  original  draw- 
ings, for  the  most  part  diagrammatic.  We  wish  also  to  express  our  thanks  to 
Dr.  Theodor  Tieken,  Dr.  F.  R.  Sherwood,  and  Dr.  D.  Loring  for  valuable 
suggestions  and  to  Dr.  W.  A.  Mansfield  in  particular,  who  read  the  original 
copy  and  made  timely  corrections. 

A  book  that  would  fail  to  give  due  consideration  to  those  structures  of  the 
body  which  can  be  easily  demonstrated  on  the  cadaver  by  any  careful  student 
would  fall  short  of  the  objects  of  this  work.  A  book  that  would  attempt  in 
approximately  400  pages  to  give  the  same  that  Morris  devotes  1400  pages  to, 
would,  to  be  charitable,  be  just  1000  pages  too  small. 

The  sequence  of  structures  revealed  by  dissection,  and  the  great  number  of 
illustrations  in  the  book,  render  an  index  almost  superfluous.  In  fact,  by  the 
aid  of  the  description  of  the  illustration  a  given  muscle  or  vessel  can  be  found 
with  certainty,  even  without  an  index.  Still,  to  make  the  book  as  convenient 
as  possible,  a  brief  index  is  appended. 

W.    T.     ECKLEY. 

C.  B.  ECKLEY. 
5816  SOUTH  PARK  AVE.,  CHICAGO. 


CONTENTS. 


PACK 

FUNDAMENTAL  PRINCIPLES  OF  ANATOMY, 9 

Anatomical  Nomenclature, , 9 

Anatomical  Tissues,  The, 13 

THE  HEAD  AND  NECK, 27 

Head,  Bones  of, 27 

Nerves, 31 

Muscles, 32 

Arteries, 37 

Veins, 39 

Glands, 4° 

Neck,  Superficial  Dissection, 43 

Deep  Cervical  Fascia, 47 

Muscles, 49 

Glands, 51 

Second  Layer  of  Deep  Cervical  Fascia, 53 

Third  Layer  of  Deep  Cervical  Fascia, 57 

Veins,  Arteries,  and  Nerves, 58 

Mouth,  The, 79 

Structures  Seen  in  Mouth, 79 

Muscles  of  Mastication, 93 

Soft  Palate 98 

Pharynx, 99 

Larynx, 106 

Nasal  Fossae,  The — Internal  Nose, m 

Coverings  of  the  Brain, 120 

Tympanum,  or  Middle  Ear, 13* 

Blood-supply  to  the  Brain, 135 

Orbit  and  its  Contents, • 139 

SHOULDER,  ARM,  FOREARM,  AND  HAND, 152 

Hand,  Bones  of,      152 

Veins, 154 

Muscles, 160 

Nerves, 162 

Arteries, 166 

Arm,  Bones  of, 168 

Arteries, 173 

Muscles, 174 

Nerves,      181 

Shoulder,  Bones  of, 186 

Axillary  Space, 188 

Veins  and  Muscles, 189 

Nerves, 195 

Arteries,    . 196 

THE  THORAX, 198 

Muscles  of, 200 

Nerves, - 201 

Arteries, 204 

Interior  of  the  Thorax, 204 

Contents, 205 

Arteries, 211 

Veins, 212 

Nerves,      214 

THE  ABDOMEN 225 

The  Walls, 225 

Spermatic  Cord,  ...             231 

Interior  View  of  Abdominal  Walls, 235 

The  Peritoneum,      238 

Abdominal  Contents, 246 

The  Sympathetic  Nerve, 261 

V 


vi  CONTENTS. 


THE  PELVIS,  CONTENTS  OF, 274 

The  Diaphragm, 285 

Female  Generative  Organs, 291 

THIGH  AND  LEG, 297 

Bones  of, 297 

Superficial  Fascia,        302 

Veins,  Nerves, 305 

Deep  Fascia, 307 

Anterior  Region  of  the  Leg,      310 

Anterior  and  Internal  Regions  of  the  Thigh, 315 

PELVIC  OUTLET  (MALE), 330 

Muscles, 331 

PELVIC  OUTLET  (FEMALE), 340 

External  and  Internal  Organs  of  Generation, 340 

POSTERIOR  PART  OF  SHOULDER,  ARM,  FOREARM,  AND  HAND, 345 

Muscles, 353 

Nerves 355 

POSTERIOR  PART  OF  LOWER  EXTREMITY, 365 

The  Popliteal  -Space, 366 

Gluteal  Region, ....  370 

Arteries  and  Nerves, 372 

Back  Part  of  the  Leg, 377 

Sole  of  the  Foot, 385 

THE  BACK,  MUSCLES  OF 394 

Nerves, 397 

Arteries, 398 

SUMMARY  OF  CRANIAL  NERVES, 398 

ARTICULATIONS — LIGAMENTS,     421 

Table  of  Various  Classes  of  Joints, 423 

Pelvis — Its  Articulations  and  Ligaments, 453 

Vertebral  Column — Its  Articulations  and  Ligaments, 460 

Thorax — Its  Articulations  and  Ligaments, 468 

SOME  INTERESTING  FACTS  ABOUT  VF.INS 473 

INDEX, 477 


LIST  OF   ILLUSTRATIONS. 


1.  Displacement  of  Cotton  by  Growing  Plants, 16 

2.  Connective  Tissue  Displaced  by  the  Artery,  Nerve,  and  Vein, 16 

3.  Triangular  Muscle, 18 

4.  Quadrangular  Muscle, 18 

5.  fusiform   Muscle, 18 

6.  Clubbed  Muscle, 18 

7.  The  Skull.      (Norma  lateralis.)     {Coloured}, 27 

8.  The  Mandible.     (Outer  view.)     (Coloured}, 28 

9.  The  Mandible.     (Inner  view.)     (Coloured} 28 

10.  The  Skull.      (Norma  facialis.)      (Coloured}, 29 

11.  The  Skull.      (Norma  basilaris.)     (Coloured}, 30 

12.  Primary  Incisions  in  Dissection  of  the  Face, 32 

13.  The   Deeper  Layer  of  the  Muscles  of  the   Face  and  Neck, 33 

14.  The  Superficial  Muscles  of  the  Head  and  Neck, 34 

15.  Scheme  of  Facial  Nerve  Communicating  with  the  Fifth  Cranial  Nerve,     ....  After  Potter  35 

16.  Superficial  Distribution  of  the  Facial  and  Other  Nerves  of  the  Head  (Coloured}, 

After  Hirschfeld  and  Leveille  36 

17.  Scheme  of  the  Facial  Artery  (Coloured}, 38 

18.  The  Superficial  Veins  and  Lymphatics  of  the  Scalp,  Face,  and  Neck  (Coloured}, 39 

19.  Showing  Schematically  the  Deep  Part  of  the  Parotid  Gland  Embracing  the  Styloid  Process,  .    .  40 

20.  The  Salivary  Glands, 41 

21.  Cervical  Triangles, 42 

22.  Superficial  Branches  of  the  Cervical  Plexus  (Coloured},      .    .    .  After  Hirschfeld  and  Leveille  46 

23.  Superficial  Lymphatics, 47 

24.  Deep  Cervical  Fascia — Transverse  Section.     Schematic,      .' 48 

25.  Muscles  of  the  Face  and  Neck, From  Gould' s  Illustrated  Medical  Dictionary  50 

26.  Scheme  of  Upper  Attachments  of  and  Special  Names  for  Deep  Cervical  Fascia, 51 

27.  Thyroid  Body,  with  Middle  Lobe  and  Levator  Muscle, 52 

28.  Scheme  of  Superior  Thyroid  Artery  (Coloured}, 53 

29.  The  Loop  Formed  by  Communicating  Branches, After  Potter  54 

30.  The  Muscles  Attached  to  the  Back  of  the  Sternum, „ 54 

31.  Vessels  and  Nerves  of  Head  and  Neck,      .    .    .  From  Gould's  Illustrated  Medical  Dictionary  59 

32.  Scheme  of  the  Lingual  Artery  (Coloured}, 60 

33.  Scheme  of  Occipital  and   Posterior  Auricular  Arteries  (Coloured}, 61 

34.  The  Common  Carotid,  the  External  and  Internal  Carotid,  and  the  Subclavian  Arteries  of  the 

Right  Side  and  Their  Branches  (Coloured}, 62 

35.  Anterior  and  Lateral  Cervical  Muscles, 64 

36.  Scheme  for  Head  and  Upper  Extremity, After  Potter  65 

37.  The  Subclavian  Vessels  (Coloured}, 66 

38.  The  Collateral   Circulation  after  Ligature  of  the   Common   Carotid  and  Subclavian  Arteries 

(Coloured}, 67 

39.  Scheme  of  the  Superior  Intercostal  Artery  (Coloured}, 68 

40.  Scheme  of  the  Vertebral  Artery  (Coloured}, 69 

41.  Scheme  of  the  Cervical  Plexus, After  Potter  75 

42.  Scheme  of  the  Brachial  Plexus, After  Potter  76 

43.  Superficial  Branches  of  the  Cervical  Plexus  (Coloured},    .    .    .    .  After  Hirschfeld  and  Leveille  78 

44.  Side  View  of  the  Tongue  with  its  Muscles, 80 

45-   Side  of  the  Face  and  Mouth  Cavity,  showing  the  Three  Salivary  Glands, 8l 

46.  Transverse  Section  through  the  Left  Half  of  the  Tongue, 82 

47.  Scheme  of  the  Right  Lingual  Artery  (Coloured}, Walshatn  83 

48.  Side  View  of  the  Muscles  of  the  Tongue, 83 

49.  The    Pterygoid   Muscles, 84 

50.  Distribution  of  the  Mandibular  Division  of  the  Trigeminal  Nerve, Henle  84 

51.  Scheme  of  Internal   Maxillary  Artery  (Colotired}, 86 

52.  The  Temporal  Muscle, 88 

53.  Scheme  of  the  Distribution  of  the  Fifth  Cranial  or  Trigeminal  Nerve,    .....    After  Potter  89 

54.  Muscles,  Vessels,  and  Nerves  of  the  Tongue, 90 

55-   The  Maxillary  Nerve  Seen  from  Without  (Colotired} Beaunis  91 

56.  The  Deeper  Layer  of  the  Muscles  of  the  Face  and  Neck, 94 

57.  The   Pterygoid   Muscles, 95 

58.  Temporo-mandibular  Articulation.      Schematic, 96 

vii 


viii  LIST   OF  ILLUSTRATIONS. 


59.  Temporo-mandibular  Articulation.     Schematic, 97 

60.  Temporo-mandibular  Articulation.     Schematic, 97 

61.  Distribution  of  the  Pneumogastric  Nerve  Viewed  from  Behind  (Coloured),   ....      Krause  loo 

62.  The  Muscles  of  the  Pharynx, .  101 

63.  The  Muscles  of  the  Pharynx, from  Gould's  Illustrated  Medical  Dictionary  102 

64.  Median  Section  of  Mouth,  Pharynx,  and  Larynx, 103 

From  Gould's  Illustrated  Medical  Dictionary 

65.  View  of  Muscles  of  Soft  Palate,  as  Seen  from  Within  the  Pharynx,  .   Modified  from  Bourgery  104 

66.  The  Muscles  of  the  Front  of  the  Neck 105 

67.  Front  View  of  the  Cartilages  of  the  Larynx, Modified  from  Bourgery  and  Jacob  106 

68.  Back  View  of  the  Cricoid  and  Arytenoid  Cartilages  ( Coloured ), 106 

Modified  from  Bourgery  and  Jacob 

69.  Posterior  View  of  Thyroid  Cartilage  with  Epiglottis, 107 

70.  Front  View  of  the  Cricoid  and  Arytenoid  Cartilages  (Coloured], 107 

Modified  from  Bourgery  and  Jacob 

71.  Nerves  of  the  Larynx.     (Posterior  view.)     (Coloured], 108 

72.  Side  View  of  the  Muscles  and  Ligaments  of  the  Larynx  (Coloured), 109 

73.  The  Posterior  Nares, 112 

74.  Section  showing  Bony  and  Cartilaginous  Septum, 112 

75.  Nerves  of  the  Nasal  Cavity  (Coloured], 113 

76.  Transverse  Section  Passing  through  the  Nasal  Fossae  and  Antra  at  the  Posterior  Extremity  of 

the  Middle  Turbinal  Bone, 114 

77.  Section  of  the  Nose,  showing  the  Turbinal  Bones  and  Meatuses,  with  the  Openings  in  Dotted 

Outline "5 

78.  The  Left  Maxilla.     (Inner  view.), 116 

79.  The  Left  Maxilla.     (Outer  view.), 117 

80.  A  Section  of  the  Skull,  showing  the  Inner  Wall  of  the  Orbit,  the  Base  of  the  Antrum,  and  the 

Spheno-maxillary  Fossa, 118- 

81.  The  Skull  in  Sagittal  Section, 121 

82.  The  Cranium  Opened  to  Show  the  Falx   Cerebri,  the  Tentorium  Cerebelli,  and  the  Places 

where  the  Cranial  Nerves  Pierce  the  Dura  Mater  (Coloured], Sappey  122 

83.  Coronal  Section  of  the  Head  Passing  through  the  Mastoid  Process 123 

84.  Schematic, 124 

85.  Coronal  Section  through  the  Great  Longitudinal  Fissure,  showing  the  Meninges, 1^5 

Key  and  Retzius 

86.  The  Venous  Sinuses  (Coloured} 127 

87.  Schematic, .» 129 

88.  Relation  of  the  Various  Structures  Passing  through  the  Cavernous  Sinus, 129 

89.  Ear  and  Tympanum, From  Gould's  Illustrated  Medical  Dictionary  133 

90.  Scheme  of  Facial  Nerve  Communicating  with  Fifth  Cranial  Nerve, After  Potter  134 

91.  The  Arteries  of  the  Brain  (Coloured}, 136 

92.  Surface  Origin  of  the  Cranial  Nerves  (Coloured}, After  Allen  Thomson. — Qiiain 

93.  Tendo  Oculi  and  Tarsal  Cartilages, 14° 

94.  Relations  of  the  Eye  and  the  Lachrymal  Excretory  Apparatus, 14° 

From  Gould's  Illustrated  Medical  Dictionarv 

95.  Schematic  Representation  to  Show  Relation  of  Periosteum  to  Tarsal  Cartilages  and  Tarsal 

Ligaments, I41 

96.  View  of  Left  Orbit  from  Above,  showing  the  Ocular  Muscles,  .  From  Hirschfeld  and  Lernlle  142 

97.  Muscles  of  the  Eye From  Gould's  Illustrated  Medical  Dictionary  142 

98.  Nerves  of  the  Orbit,  from  the  Outer  Side  (Coloured), 143 

From  Sappey,  after  Hirschfeld  and  Leveille 

99.  Left  Eyeball  Seen  in  its  Normal  Position  in  the  Orbit,  with  View  of  the  Ocular  Muscles,    .    .  144 

After  Merkel,  modified 

100.  Muscles  of  the  Eye.    Tendon  or  Ligament  of  Zinn, 144 

From  Gould's  Illustrated  Medical  Dictionary 

101.  Diagrammatic  Representation  of  Origins  of  Ocular  Muscles  at  the  Apex  of  the   Right  Orbit,  145 

After  Schwalbe,  slightly  altered 

102.  Vertical   Section  through  the   Eyeball  and  Orbit  in  the  Direction  of  the  Orbital  Axis,  with 

Closed  Eyelids  (Coloured}, ',    .    .    .      After  Schwalbe,  modified  146 

103.  The  Ophthalmic  Artery  and  Vein  (Coloured) 14° 

104.  Lachrymal  Apparatus, After  Schwalbe  147 

105.  Superficial  Veins  and  Lymphatics  of  the  Forearm  and  Arm  (Coloured}, 153 

106.  Distribution  of  Cutaneous  Nerves  on  the  Anterior  and  Posterior  Aspects  of  the  Superior  Ex- 

tremity   154 

107.  Diagram  of  the  Great  Palmar  Bursa, '55 

108.  The  Left  Hand.      (Dorsal  surface.)     (Coloured}, 156 

109.  The  Left  Hand.     (Palmar surface.)    (Coloured}, 157 

no.   The  Superficial  Muscles  of  the  Palm  of  the  Hand, 158 

111.  Superficial  Nerves  of  the  Palm  (Coloured}, Ellis  159 

112.  The  Deeper  Muscles  of  the  Palm  of  the  Hand, 160 

113.  Anastomoses  and   Distribution  of  the  Arteries  of  the  Hand  (Coloured) 161 

114.  The  Pronator  Quad  rat  us  and  Deep  View  of  the  Palm, 163 

115.  The  Palmar  Interossei, 164 


LIST   OF  ILLUSTRATIONS.  ix 

• 

FK...  PAGE 

116.  Anastomoses  and  Distribution  of  the  Arteries  of  the  Hand  (Coloured], 165 

117.  The  Arteries  of  the  Forearm  with  the  Deep  Palmar  Arch  (Coloured'], 172 

118.  The  Bend  of  the  Elbow  with  the  Superficial  Veins  (Coloured  ), 173 

119.  The  Brachial  Artery  at  the  Bend  of  the  Elbow  (Coloured], 174 

120.  Front  of  the  Forearm  :   First  Layer  of  Muscles, 175 

121.  Superficial  Muscles  of  Palmar  Aspect  of  Forearm, 176 

From  Gould'' 's  Illustrated  Medical  Dictionary 

122.  Front  of  the  Forearm  :  Second  Layer  of  Muscles, 177 

123.  The  Lower  Part  of  the  Axillary,  the  Brachial,  and  the  Radial  and  Ulnar  Arteries  (Coloured},  178 

124.  The  Left  Ulna  and  Radius.     (Antero-internal  view.)     (Coloured), 179 

125.  Front  of  the  Forearm:  Third  Layer  of  Muscles, 180 

126.  Superficial  View  of  the  Front  of  the  Upper  Arm, 181 

127.  Deep  View  of  the   Front  of  the  Upper  Arm, 182 

128.  Deep  Muscles  of  Palmar  Aspect  of  Forearm,      .     From  Gould' 's  Illustrated 'Medical Dictionary  183 

129.  The  Left  Humerus  with  a  Supracondyloid  Process  and  some  Irregular  Muscle  Attachments. 

(Anterior  view.)      (Coloured), 184 

130.  The  Pectoralis  Major  and  Deltoid, 188 

131.  The  Left  Clavicle.     (Superior  surface.)     (Coloured), 188 

132.  The  Clavi-pectoral  Fascia,      189 

133.  To  Show  Schematically  the*  Distribution  of  the   Deep  Cervical   Fascia  Above  and  Below  the 

Clavicle,      190 

134.  The  Left  Clavicle.     (Inferior  surface.)     (Coloured), 191 

135.  Serratus  Magnus.      The  Inner  Wall  of  the  Axilla, 192 

136.  Front  View  of  the  Scapular  Muscles.     The  Posterior  Wall  of  the  Axilla, 193 

137.  The  Lower  Part  of  the  Axillary,  the  Brachial,  and  the  Radial  and  Ulnar  Arteries  (Coloured),  194 

138.  First  and  Second  Ribs  (Coloured), 198 

139.  The  Sternum, 199 

140.  The  Intercostal  Muscles, 200 

141.  The  Intercostal  Nerves, 201 

142.  The  Muscles  Attached  to  the  Back  of  the  Sternum, 202 

143.  Scheme  of  the  Internal   Mammary  Artery  (Coloured), 203 

144.  Anterior  View  of  the  Lungs:  Pericardium, Modified  from  Bourgery  205 

145.  Anterior  View  of  the  Thorax  with  Chest  Wall  Removed,  showing  the  Lungs, 206 

Modified  front  Bonrgery 

146.  Invagination  of  Pleura, 207 

147.  Thymus  Gland  in  a  Child  at  Birth, 209 

148.  Scheme  of  the  Fcetal  Circulation, 210 

149.  Anterior  View  of  Fcetal  Heart,  Vessels,  and  Lungs, 211 

150.  The  Arch  of  the  Aorta,  the  Thoracic  Aorta,  and  the  Abdominal  Aorta,  with  the  Superior  and 

Inferior  Vena  Cava  and  the  Innominate  and  Azygos  Veins  (Coloured), 212 

151.  The  Heart  and  Great  Vessels,  with  the  Root  of  the  Lungs,  Seen  from  Behind  (Coloured),    .  214 

152.  The  Sympathetic  System  of  Nerves, After  Potter  215 

153.  The  Arch  of   the   Aorta,   with  the  Pulmonary  Artery  and    Chief    Branches  of    the   Aorta 

(Coloured), 217 

154.  Anterior  View  of  the  Right  Chambers  of  the  Heart,  with  the   Great  Vessels, 219 

155-    I  he    Heart,  with  the   Arch  of  the  Aorta,  the   Pulmonary  Artery,  the  Ductus   Arteriosus,  and 

the  Vessels  Concerned  in  the  F(etal  Circulation  (Coloured), 220 

156.  Anterior  View  of  the  Heart,  showing   its  Arteries  and  Veins  (Coloured), 222 

157.  Posterior  View  of  the    Heart,  showing  its  Arteries  and  Veins  (Coloured), 223 

158.  Cutaneous  Nerves  of  the   Thorax  and  Abdomen,  Viewed  from  the  Side,  ....    After  Hcnle  226 

159.  External  Oblique  and  Ilio-tibial  Band, 227 

160.  The  Pectoralis  Minor,  Obliquus  Internus,  Pyramidalis,  and   Rectus  Abdominis, 228 

161.  Obliquus  Externus  and  Fascia  Lata, 229 

162.  Transversalis  Abdominis   and   Sheath  of  Rectus, 230 

163.  Internal  Oblique  and  Transversalis  Abdominis  Muscles, 232 

From  Gould's  Illustrated  Medical  Dictionary 

164.  Dissection  of  the  Lower  Part  of  the  Abdominal  Wall  from  Within,  the   Peritoneum  having 

been  Removed,      ,    .    Wood  235 

165.  Irregularities  of  the  Obturator  Artery, After  Gray  237 

166.  Vessels  of  the  Small  Intestine, 238 

167.  Showing  Partial  and  Complete  Investment  of  Organs  by  Peritoneum, 239 

168.  Showing  Retro-peritoneal  Locality, 239 

169.  Showing  Aorta  and  Primitive  Mesentery, 240 

170.  Showing  Loss  of  Endothelium  at  Contact  Point  of  Visceral  and  Parietal  Peritoneum,    ....  240 

171.  Showing  Simple  Visceral  and  Parietal  Layers  of  Peritoneum  with  Cavity  Between  Them,    .    .  241 

172.  Diagram  of  the  Primitive  Alimentary  Canal, 243 

173.  Diagrams  showing  (A)  the   Formation  of  the  Great  Omentum,  and  (E)  the  Rotation  of  the 

Intestinal  Canal, 244 

174.  The  Cceliac   Artery  and  its  Branches  (Coloured), 247 

175.  The  Viscera  as  Seen  on  Fully  Opening  the  Abdomen  without  Disarrangement  of  the  Internal 

Parts, After  Sarazin  247 

176.  The  Viscera  of  the  Foetus, Riidinger  249 

177.  Relation  of  Structures  at  and  below  the  Transverse  Fissure, Thane  251 


x  L/ST   OF  ILLUSTRATIONS. 

» 

FIG.  ru.K 

178.  The  Inferior  Surface  of  the  Liver, 254 

179.  Posterior  Surface  of  the  Liver, 254 

180.  The  Superior  Mesenteric  Artery  and  Vein  (Coloured  ), 257 

181.  The  Inferior  Mesenteric  Artery  and  Vein  (Coloured), 258 

182.  Diagram  showing  Anterior  Relations  of  Kidneys  and  Suprarenal  Bodies 259 

183.  The  Abdominal  Aorta  and  its  Branches,  with  the  Inferior  Vena  Cava  and  its  Tributaries,    .    .  260 

184.  The  Sympathetic  System  of  Nerves, After  Potter  262 

185.  The  Sympathetic  System  of  Nerves, After  Potter  264 

l8b.   Showing  Schematically  a  Sensory  Reflex  Circuit, 269 

187.  Showing  Schematically  a  Motor  Reflex  Circuit, 270 

188.  To    Show    Relation  of  Abdominal  Sympathetic    Nerves  to  (l)  Solar  Plexus,  and  (2)  to  the 

Ganglion  at  the  Root  of  the  Artery, 271 

189.  Lumbar  Portion  of  the  Gangliated  Cord,  with  the  Solar  and  Hypogastric  Plexuses  (Coloured),  272 

(After  ilenle) 

190.  Branches  of  the  Lumbar  and  Sacral  Plexus,  Viewed  from  Before  (Coloured}, 276 

After  Hirschfeld  and  Leveillc 

191.  Side  View  of  Pelvis  and  Upper  Third  of  Thigh,  with  the  External   Iliac,  Internal   Iliac,  and 

Femoral  Arteries  and  their  Branches  (Coloured), 277 

192.  Muscles  of  the  Floor  of  the  Pelvis .    .  278 

193.  Diagram  of  the  Lumbar  and  Sacral  Plexuses, Modified  from  Paterson  280 

194.  A  Dissection  of  the  Lumbar  and  Sacral  Plexuses,  from  Behind  (Coloured), 281 

195.  Diaphragm, 286 

196.  The  Left  Hip-bone.     (Internal  surface.)     (Coloured), 287 

197.  Psoas,  Iliacus,  and  Quadratus  Lumborum, 288 

198.  Arrangements  of  Lumbar  Aponeurosis  at  Level  of  Third  Lumbar  Vertebra, 289 

199.  The  Sacrum  and  Coccyx.     (Anterior  view.)     (Coloured), 290 

200.  Muscles  of  the  Floor  of  the  Pelvis, 290 

201.  The  Broad  Ligament  and  its  Contents,  seen  from  the  Front, After  Sappey  291 

202.  Representing  Schematically  the  Relation  of  the  Ureter  to  the  Broad  Ligament  of  the  Uterus,  292 

203.  Frontal  Section  of  the  Virgin  Uterus, After  Sappey  292 

204.  Scheme  of  the  Ovarian  and  Uterine  and  Vaginal  Arteries  (Coloured),- 293 

205.  The  P'emale  Organs  of  Generation, Modified  from  Sappey  293 

206.  Sagittal  Section  of  the  Virgin  Uterus,       ' After  Sappey  294 

207.  The  Left  Tibia  and  Fibula.      (Anterior  view.)      (Coloured), 300 

208.  The  Left  Tibia  and  Fibula.     (Posterior  view.)     (Coloured), 301 

209.  Distribution  of  Cutaneous  Nerves  on  the  Anterior  Aspect  of  the  Inferior  Extremity,  ....  303 

210.  The  Superficial  Veins  and  Lymphatics  of  the  Lower  Limb  (Coloured), 304 

211.  Superficial  Dissection  of  the  Front  of  the   Thigh, Hirschfeld  and  Lerei/le  305 

212.  The  Femoral   Ring  and  Saphenous  Opening, After  Holden  309 

213.  The  Muscles  of  the  Front  of  the  Leg, 311 

214.  The  Anterior  Tibial  Artery,  Dorsal  Artery  of  the   Foot,  and  Anterior   Peroneal'  Artery,  and 

their  Branches  (Coloured),      312 

215.  The  Left  Foot.     (Dorsal  surface.)     (Coloitred), 313 

216.  The  Left  Tibia  and  Fibula.     (Anterior  View.)     (Coloured), 314 

217.  Branches  of  the  External  Popliteal  Nerve  (Coloured), 3*6 

218.  Muscles  of  the  Front  of  the  Thigh, 317 

219.  Anterior  Crural  and  Obturator  Nerves, 318 

220.  The  Deep  Muscles  of  the  Front  of  the  Thigh, 319 

221.  Pectineus  and  Adductor  Longus, 32° 

222.  Adductor  Brevis  and  Adductor  Magnus, 320 

223.  The  Femoral  Artery  in  Scarpa's  Triangle  (Coloured), 322 

224.  Obliquus  Externus  and  Fascia  Lata, 323 

225.  Muscles  of  the  Anterior  Aspect  of  the  Body,    .   From  Gould1  s  Illusti ated  Medical  Dictionary  324 

226.  The    Left  Hip-bone.      (Posterior  view.)     (Coloured) 325 

227.  The  Left  Femur.     (Posterior  view.)     (Coloured), 326 

228.  The  Left  Femur.     (Anterior  view.)     (Coloured), 327 

229.  The  Male  Perineum  (Coloured), Modified  from  Hirschfeld  unif  Lcreill,'-  331 

230.  The  Arteries  of  the  Perineum   (Coloured), 332 

231.  Transverse  Section  through  the  Body  of  the  Penis  (Coloured), 333 

232.  The  Male  Urethra,  cleft  dorsally  t<>  Show  Ventral  Mucous  Wall, ....  335 

233.  Diagram  of  the  Superficial  and  1  )eep  Triangular  Ligaments  (Coloured), 330 

234.  Muscle  of  Guthrie 3.^7 

235.  Muscle  of  Guthrie  and  Wilson, 337 

236.  V:isa  I  h-feientia  and  Vesiculae  Seminales, (fter  Sappey  338 

237.  Diagrammatic  Representation  of  the  Peiineal   Structures  in  the  Female 341 

238.  External  Genitals  of  the  Virgin,  with  Diaphragmatic  Hymen, -{flcr  Sappey  342 

239.  Sri  lion  of  the  Female  Pelvis,     ...             After  Henle  343 

240.  The  Left  Scapula.     (Dorsal  surface.)     (Coloured), 345 

241.  Distribution  of  Cutaneous  Nerves  on  the  Anterior  and  Posterior  Aspects  of  the  Superior  Y.\ 

tremity, 34^ 

242.  A    Dissection   of  the  Cutaneous  Nerves   on    the  Dorsal    Aspect  of  the  Hand    and  Fingers 

H.St.J.B.  347 

243.  Muscles  of  the  Radial  Side  and  the  Back  of  the  Forearm 349 


LIST   OF  ILLUSTRATIONS,  xi 

FIG.  PAGE 

244.  Tendons  upon  the  Dorsum  of  the  Hand, 350 

245.  The  Deep  Layer  of  the  Back  of  the  Forearm, 351 

246.  The  Left  Ulna  and  Radius.     (Postero-external  view.)     (Coloured), 352 

247.  The  Back  of  the  Forearm,  with  the  Posterior  Interosseous  Artery  and  Branches  of  the  Radial 

at  the  Back  of  the  Wrist  (Coloured), 353 

248.  The  Dorsal  Interossei, 354 

249.  The  Posterior  Circumflex  Artery  (Coloured), 356 

250.  First  Layer  of  the  Muscles  of  the  Back, 357 

251.  Back  View  of  the  Scapular  Muscles  and  Triceps, 358 

252.  Posterior  View  of  the  Shoulder-joint,  showing  also  the  Acromio-clavicular  Joint  and  the  Proper 

Ligaments  of  the  Scapula, 359 

253.  Triceps  Brachialis,  Posterior  Aspect, from  Gould's  Illustrated  Medical  Dictionary  360 

254.  The  Dorsal  Scapular  Artery  (Coloured), 361 

255.  Distribution  of  Cutaneous  Nerves  on  the  Posterior  Aspect  of  the  Inferior  Extremity 367 

256.  Superficial  Muscles  of  the  Back  of  the  Thigh  and  Leg,      368 

257.  Gluteus  Maximus  Muscle, From  Gould ' s  Illustratea  Medical  Dictionary  370 

258.  A  Dissection  of  the  Nerves  in  the  Gluteal  Region  (Coloured), 371 

259.  The  External  Rotators  and  the  Hamstring  Muscles, 373 

260.  Deep  Dissection  of  the  Gluteal  Region, 374 

261.  Horizontal  Section  of  the  Knee-joint.      (One-half.), 375 

262.  Short  Head  of  Biceps  and  Semimembranosus,  .  From  Gould's  Illustrated  Medical  Dictionary  376 

263.  Long  Head  of  Biceps  and  Semitendinosus,    .    .  From  Gould's  Illustrated  Medical  Dictionary  376 

264.  Deep  View  of  the  Popliteal  Space, Hirschfeld  and  Leveille  378 

265.  The  Deep  Muscles  of  the  Hack  of  the  Leg 379 

266.  Relations  of  the  Popliteal  Artery  to  Bones  and  Muscles  (Coloured,) 380 

267.  The  Left  Tibia  and  Fibula.    (Posterior  view.)   (Coloured), 381 

268.  The  Left  Foot.      (Plantar  surface.)    (Coloured), 382 

269.  Muscles  of  the  Leg,  External  Aspect,      ....  Front  Gould's  Illustrated  Medical  Dictionary  383 

270.  Second  Layer  of  the  Muscles  of  the  Sole, 385 

271.  First  Layer  of  the  Muscles  of  the  Sole, 386 

272.  Superficial  Nerves  in  the  Sole  of  the  Foot  (Coloured), Ellis  387 

273.  The  Plantar  Arteries  (Coloured), 388 

274.  Third  Layer  of  the  Muscles  of  the  Sole, 389 

275.  Fourth  Layer  of  the  Muscles  of  the  Sole, 591 

276.  Horizontal  Section  through  the  Intervertebral  Disc  and  Ribs, 396 

277.  Showing  the  Anterior  Common  Ligament  of  the  Spine,  and  the  Connection  of  the  Ribs  with 

the  Vertebne, 396 

278.  The  Occipital.      (External  view.)     (Coloured), 397 

279.  Distribution  of  the  Posterior  Primary  Divisions  of  the  Spinal  Nerves,   ....        399 

280.  First  Layer  of  Muscles  of  the  Back, 401 

281.  The  Levator  Anguli  Scapulas  and  Rhomboidei, 402 

282.  The  Third  and  Fourth  Layers  of  the  Muscles  of  the  Back, ...  403 

283.  The  Fifth  Layer  of  the  Muscles  of  the  Back, 404 

284.  The  Fifth  Layer  of  the  Muscles  of  the  Back,  after  Separating  the  Outer  and  Middle  Divisions,  406 

285.  The  Sixth  Layer  of  the  Muscles  of  the  Back, 408 

286.  First  Cranial  Nerve,  Olfactory Afttr  Potter  412 

287.  Second  Cranial  Nerve,  Optic, ..',......     After  Potter  412 

288.  Third  Cranial  Nerve,  Motor  Oculi, After  Potter  413 

289.  Fourth  Cranial   Nerve,  Trochlear, After  Potter  413 

290.  Fifth  Cranial  Nerve After  Potter  414 

291.  Seventh  Cranial  Nerve,  Facial,  or  Portia  Dura,      After  Potter  415 

292.  Box  Illustration  of  Seventh  Cranial  Nerve  in  Relation  to  the  Middle  Ear  or  Tympanum,     .    .  416 

293.  Eighth  Pair  of  Cranial  Nerves, After  Potter  418 

294.  Vertical  Section  through  the  Condyle  of  Jaw  to  Show  the  Two  Synovial  Sacs  and  the    Inter- 

articular  Fibro-cartilage,       .             425 

295.  External  View  of  Temporo  mandibular  Joint, 427 

296.  Internal  View  of  Temporo-mandibular  Joint, 427 

297.  Outer  View  of  the   Shoulder-joint,  showing  the  Coraco-humeral    and  Transverse  Humeral 

Ligaments, 428 

298.  Posterior  View  of  the   Shoulder-joint,  showing  also  the  Acromio-clavicular   Joint  and  the 

Proper  Ligaments  of  the  Scapula, 429 

299.  Anterior  View  of  Shoulder,  showing  also  Coraco-clavicular  and   Coraco-acromial  Ligaments,  430 

300.  Anterior  View  of  Sterno-clavicular  Joint, 431 

301.  Orbicular  Ligament, 433 

302.  External  View  of  the   Elbow-joint, 433 

303.  Internal  View  of  the  Elbow-joint, 434 

304.  Anterior  View  of  Wrist, 434 

305.  Posterior  View  of  Wrist 435 

306.  Synovial  Membranes  of  Wrist,  Hnnd,  and  Fingers, 436 

307.  Posterior  View  of  the  Capsule  of  the  Hip-joint, 438 

308.  Anterior  View  of  the  Capsule  of  the  Hip-joint, 439 

309.  Hip-joint  after  Dividing  the  Capsular  Ligament  and    Disarticulating  the    Femur, 441 

310.  Anterior  View  of  the   Internal   Ligaments  of  the  Knee-joint, 441 


xii  LIST   OF  ILLUSTRATIONS. 

FIG.  PAGE 

311.  Posterior  View  of  the  Knee-joint, 442 

312.  Structures  Lying  on  the  Head  of  the  Tibia.     (Right  knee.), 442 

313.  Anterior  View  of  the  Knee-joint,  showing  the  Synovial  Ligaments, 443 

314.  The  Left  Foot.     (Plantar  surface.)     (Coloured), 446 

315.  The  Left  Foot.     ( Dorsal  surface. )     (Coloured), 447 

316.  Section  to  Show^  the  Synovial  Cavities  of  the  Foot, 448 

317.  External  View  of  the  Ligaments  of  the  Foot  and  Ankle, 449 

318.  Inner  View  of  the  Ankle  and  the  Tarsus,  showing  the  Groove  for  the  Tendon  of  the  Tibialis 

Posticus,      450 

319.  Ligaments  of  the  Sole  of  the  Left  Foot, 450 

320.  Ligaments   seen  from  the  Back  of  the  Ankle-joint, 452 

321.  Right  Innominate  Bone,  External  Aspect,     .    .From  Gould 's  Illustrated  Medical  Dictionary  453 

322.  Pelvis,  Antero-superior  View,  Superior  Strait,  .  From  Gould  's  Illustrated  Medical  Dictionary  453 

323.  Femur,  Posterior  Aspect, From  Gould'' s  Illustrated  Medical  Dictionary  454 

324.  Anterior  View  of  the  Symphysis  Pubis  (Female,  showing  Greater  Width  between  the  Bones),  455 

325.  Posterior  View  of  the  Symphysis  Pubis,  showing  the  Backward  Projection  of  the  Symphysial 

Substance  and  the  Decussation  of  the  Fibres  from  the  Inferior  Pubic  Ligament, 455 

326.  Anterior  View  of  the  Symphysis  Pubis   (Male)   showing  Decussation  of  the  Fibres  of  the 

Anterior  Ligament, 455 

327.  Anterior  View  of  the  Pelvis, 456 

328.  Sacro-sciatic  Ligaments.     (Posterior  view.), 457 

329.  Vertical  Antero-posterior  Section  of  the  Pelvis,       458 

330.  Coccyx,  Anterior  Aspect, From  Gould'1  s  Illustrated  Medical  Dictionarv  459 

331.  Vertebral  Column,  Lateral  Aspect, From  Gould's  Illustrated  Medical  Dictionary  459 

332.  Posterior  Common  Ligament  of  the  Spine.     (Thoracic  region.), 460 

333-   Ligamenta  Subflava  in  the  Lumbar  Region, 461 

334.  Morphology  of  the  Transverse  and  Articular  Processes, 462 

335.  The  Interspinous  and  Supraspinous  Ligaments  in  the  Lumbar  Region, 463 

336.  Vertical  Transverse  Section  of  the  Spinal  Column  and  the  Occipital  Bone  to  Show  Ligaments,  464 

337.  Seventh  Cervical  Vertebra,  Postero- superior  View  ;  Dorsal  Vertebra,  Antero-superior  View  ; 

First  Dorsal  Vertebra,  Lateral  View ;  Eleventh  Dorsal  Vertebra,  Lateral  View  ;  Twelfth 

Dorsal  Vertebra,  Lateral  View, From  Gould'1  s  Illustrated  Medical  Dictionary  465 

338.  Occipital  Bone,  Postero-inferior  View,     .    .    .    .  From  Gould'1  s  Illustrated  Medical  Dictionary  465 

339.  Anterior  View  of  the  Upper  End  of  the  Spine, 466 

340.  Showing  the  Anterior  Common  Ligament  of  the  Spine,  and  the  Connection  of  the  Ribs  with 

the  Vertebrae 466 

341.  Vertical  Antero-posterior  Section  of  Spinal  Column  through  Median  Line,  showing  Ligaments,  467 

342.  The  Superficial  Layer  of  the  Posterior  Common  Vertebral  Ligament  has  been   Removed  to 

Show  its  Deep  or  Short  Fibres, 468 

343.  Ribs  of  Left  Side,  Posterior  Aspect, From  Gould 's  Illustrated  Medical  Dictionary  469 

344.  Thorax,  Anterior  View, From  Gould's  Illustrated  Medical  Dictionary  469 

345.  The  Capsular  Ligaments  of  the  Costo-vertebral  Joints, 470 

346.  Horizontal  Section  through  the  Intervertebral  Disc  and  Ribs, 471 

347.  The  Sternum, 472 


PRACTICAL    ANATOMY. 


FUNDAMENTAL  PRINCIPLES  OF  ANATOMY. 


In  the  following  introductory  pages  will  be  found  some  rules  and  observations 
on  anatomical  study  which  the  student  must  learn,  if  he  would  become  master 
of  dissecting-room  technique.  Under  the  above  heading  are  considered  : 

1.  Anatomical  nomenclature. 

2.  Anatomical  tissues  applied. 

3.  Functions  of  periosteum. 

4.  Eminences  and  depressions  of  bone. 

5.  Anatomical  weak  points. 

6.  Anatomical  visceral  roots. 

7.  Anatomical  antagonism  in  muscles  and  nerves. 

8.  Shape  of  muscle  an  index  to  the  nerve-supply. 

9.  Hilton's  law  regarding  articular  nerves. 

10.  Non-apposition  of  anatomical  structures. 

1 1.  Anatomical  sheaths  ;  rationale  of  their  formation. 

12.  Dissection  defined. 

13.  Fanciful  names  for  muscles. 

14.  Sphincters  and  orbiculars  distinguished. 

15.  Geometrical  usage  in  anatomy. 

1 6.  Substantive  adjectives  :    use  of. 

17.  Law  of  projectiles  :  its  application  to  grooves. 

1 8.  Application  of  law  of  projectiles  to  reflex  pain. 

19.  Fasciae,  superficial  and  deep. 

20.  Aponeuroses  :  varieties  of. 

21.  Origin  and  insertion  of  muscle. 

22.  Synovial  membranes. 

23.  Serous  and  mucous  membranes. 

24.  Anatomical  fibrous  arches. 

ANATOMICAL  NOMENCLATURE. 

This  chapter  is  intended  to  explain  in  advance  some  of  the  features  of 
anatomical  nomenclature,  a  knowledge  of  which  will  facilitate  an  understanding 
of  what  is  seen,  read,  and  heard. 

Anatomical  nomenclature  is  the  technical  language  of  anatomy.  Chemistry, 
music,  law,  all  the  arts  and  sciences,  have  their  nomenclature.  One  of  the 
surest  indications  of  thorough  system  in  any  science  is  the  nomenclature  of  that 
science,  if,  indeed,  a  department  can  be  called  scientific  without  a  nomenclature. 

9 


io  PRACTICAL  ANATOMY. 

Compound  words  are  used  to  express  the  collective  sense  arising  from 
anatomical  union,  conjunction,  and  relation.  Words  of  this  class  are  met  many 
times  daily,  not  only  in  anatomy,  but  in  every  branch  of  the  medical  sciences. 
Sterno-hyoid,  omo-hyoid,  musculo-aponeurotic,  temporo-mandibular,  express 
relations  in  anatomy  that  are  thoroughly  understood  by  the  physician. 

The  principle  in  compound  words  is  clearly  in  the  nature  of  a  copartner- 
ship. In  the  expression,  radio-ulnar  articulation,  radius  and  ulna  are  both 
concerned  in  the  formation  of  this  joint ;  each  bone  has  an  anatomical  interest  in 
the  joint,  hence  a  physiological  responsibility.  The  name  of  an  articulation, 
then,  to  represent  fully  the  copartnership,  must  include  all  the  parties  to 
the  contract.  The  number  of  partners  must  be  two  ;  it  may  be  any  number  : 
(i)  Sterno-cleido-mastoid ;  (2)fronto-malo-spheno-ethmo-lachrymo-maxillo-nasal 
articulation. 

RULE  FOR  WRITING  MINIMAL  COMPOUND  WORDS. — Place  the  shorter  word 
first  in  the  ablative,  o ;  the  larger  word  second,  in  some  euphonious  adjective  ; 
connect  the  two  words  by  a  hyphen.  The  rule  for  writing  maximal  compound 
words  is  the  same.  Here  the  shortest  word  is  placed  first ;  it  and  all  succeeding 
words  end  in  o  except  the  last. 

Exceptions  to  the  rule  are  (i)  to  indicate  direction  of  motion  ;  (2)  to  conform 
to  national  or  individual  ideas  of  euphony.  We  may  express  the  direction  taken 
by  a  missile  passing  from  the  radial  to  the  ulnar  side  thus  :  radio-ulnarly,  or  the 
opposite  by  ulno-radially.  In  many  cases  euphony  demands  the  larger  word 
first.  Where  exceptions  are  as  important  as  these,  they  seem  to  acquire  the 
dignity  of  law ;  hence  remember  in  writing  compound  words  either  word  may 
be  placed  first. 

Anatomical  Opposites  in  Location  or  Function. — The  fundamental  idea  in 
each  is  antagonism  ;  of  location  in  the  former,  of  function  in  the  latter.  An  under- 
standing of  one  opposite  implies  the  necessity  of  the  other's  presence  :  anterior 
surface  of  the  scapula  is  positive  evidence  of  the  existence  of  a  posterior  surface 
of  the  scapula.  The  principle  is  sometimes  abused — e.  g.,  internal  iliac  muscle  is 
referred  to  in  some  texts  ;  there  is  no  external  iliac  muscle  ;  etc.  These  redun- 
dancies, while  undesirable,  since  they  are  misleading,  are  nevertheless  tolerated 
in  some  good  works  on  anatomy  by  a  sort  of  license  that  characterizes  the 
unique  redundancy  in  legal  and  scientific  phraseology.  Musculus  flexor  carpi 
radialis  and  musculus  extensor  carpi  radialis  are  anatomical  examples  of  ana- 
tomical structures  opposite  in  function.  Remember,  too,  that  structures  opposite 
in  function  are  usually  also  opposites  in  point  of  location  on  the  part  of  the 
body  in  which  found. 

EXAMPLES  OF  COMMON  OPPOSITES. 

Superior  extremity.  Inferior  extremity. 

Anterior  surface.  Posterior  surface. 

Ventral  mesentery.  Dorsal  mesentery. 

Central  organ.  Peripheral  organ. 

Somatic  nerves.  Sympathetic  nerve?. 

Proximal  end.  Distal  end. 

Tendinous  origin.  Tendinous  insertion. 

Flexor  muscles.  Extensor  muscles. 

Pronator  agents.  Supinator  agents. 

Greater  trochanter.  Lesser  trochanter. 

Base  of  lung.  Apex  of  lung. 

Levator  muscle.  Depressor  muscle. 

Gluteus  maximus.  Gluteus  minimus. 

Pectoralis  major.  Pectoralis  minor. 

Peroneus  longus.  Peroneus  brevis. 

Colica  dextra.  Colica  sinistra. 

Centripetal  vessels.  Centrifugal  vessels. 

Compact  tissue.  Cancellous  tissue. 

Longitudinal  axis.  Transverse  axis. 


FUNDAMENTAL  PRINCIPLES  OF  ANA  TOMY. 


1 1 


CLASSICAL  WORDS  IN  COMMON  USE  IN  ANATOMY. 

A'anu'.          Gen.  Sing.  Plural.  Gen.  Plural.  English. 

Fascia,  ...  se,  ....  Fasciae.  Fasciarum.  Sash. 

Glandula,  .    .  ae,  .    .    .    .  Glandulas.  Glandularum.  Gland. 

Vena,    .    .    .  ae Venae.  Venarum.  Vein. 

Artena,  .    .    .  ae Arteriae.  Arteriarum.  Artery. 

Cartilage,  .    .  inis,   .    .    .  Cartilagines.  Cartilaginum.  Cartilage. 

Chondrum,  .  i,     ....  Chondra.  Chondrium.  Cartilage. 

Tendo,  ...  is,  ....  Tendines.  Tendinium.  Tendon. 

Musculus,     .  i Musculi.  Musculorum.  Muscle. 

Nervus,     .    .  i Nervi.  Nervorum.  Nerve. 

Vas is,  ....  Vasa.  Vasorum.  Vessel. 

Os, sis,     .    .    .  Ossa.  Ossium.  Bone. 

Os ris,     .    .    .  Ores.  Orium.  Mouth. 

Aponeurosis,  is,  ....  Aponeuroses.  Aponeurosium.  Band. 

Costa,    ...  ae,  ....  Costae.  Costarum.  Rib. 

Viscus,  ...  us,      ...  Viscera.  Organ. 

Pons,      .    .    .  tis,     .    .    .  Pontes.  Pentium.  Bridge. 

Trochlea,  .    .  ae Trochleae.  Trocharum.  Pulley. 

Gaster,  Stomach. 

Intestinum,  .  i Intestini.  Intestinorum.  Intestine. 

Many  adjectives  are  in  use,  as  magnus,  longus,  brevis,  latus,  profundus,  sub- 
limis,  orbicularis  ;  they  are  declined  and  used  as  the  nature  of  the  case  would 
indicate. 

Rationale  of  Naming  of  Certain  Muscles. — It  is  important  that  the  student 
should,  early  in  his  course  of  dissection,  understand  why  certain  muscles  are 
named  as  they  are  named  in  the  books.  In  fact,  the  student  should  have  a 
knowledge  of  the  principle  involved  in  this  part  of  the  nomenclature.  To  one 
unfamiliar  with  this  principle  the  names  tibialis  antictts,  pronator  quadratics, 
extensor  minimi,  may  seem  perfect  and  complete  designations.  The  impression, 
however,  is  erroneous,  as  the  above  terms  are  incomplete.  In  other  words,  the 
terms  above  given  are  only  abbreviations,  and  are  properly  used  when  the 
manner  by  which  usage  sanctions  them  is  understood.  The  principle  is  this  : 
The  complete  technical  name  of  a  muscle  contemplates  :  (i)  The  structure  ;  (2)  the 
structure  in  the  capacity  of  an  agent ;  (3)  an  agent  of  something  ;  (4)  an  agent 
adjectively  qualified  in  such  a  manner  as  to  distinguish  it  from  others  of  a  syner- 
gistic  class. 

STRUCTURE.    AGENT.    AGENT  OF  WHAT.     DESCRIPTIVE    ADJECTIVES. 


Mttsculus 

flexor 

carpi 

Musculus 

flexor 

carpi 

Musculus 

flexor 

cubiti 

Musculus 

extensor 

carpi 

Musculus 

extensor 

carpi 

Musculus 

extensor 

digitorum 

Musculus 

extensor 

digiti 

Musculus 

levator 

labii 

radialis 

ulnaris 

bicipitalis 

radialis 

radialis 

communis 

minimi 

superioris 


longior 
brevior 


We  unconsciously  acquire  a  habit  of  using  the  abbreviated  name,  and  this 
explains  in  part  the  lamentable  fact  that  so  many  students  leave  school  with  a 
memory  well  stored  with  words — words  numerous,  ponderous,  classical — words 
which,  by  virtue  of  their  abbreviational  arrangement,  leave  on  the  memory  no 
notion  of  the  physiological  function  of  the  muscle.  At  times  the  habit  of  thinking 
of  names  of  muscles  almost  makes  us  fail  to  recognize  the  full  name.  The 
following  table  will  illustrate  this  point : 


ANATOMICAL  NAME. 


TECHNICAL  NAME. 


Tibialis  anticus Musculus  flexor  tarsi  tibialis  anticus. 

Tibialis  posticus Musculus  extensor  tarsi  tibialis  posticus. 

Peroneus  longus Musculus  extensor  tarsi  peroneus  longus. 


12  PRACTICAL  ANATOMY. 

ANATOMICAL  NAME.  TECHNICAL  NAME. 

Peroneus  brevis, Musculus  extensor  tarsi  peroneus  brevis. 

Peroneus  tertius Musculus  flexor  tarsi  peroneus  tertius. 

Triceps,    .    .    . ' Musculus  extensor  cubiti  tricipitalis. 

Biceps, Musculus  flexor  cubiti  bicipitalis. 

Supinator  longus Musculus  supinator  brachio-radialis  longior. 

Supinator  brevis Musculus  supinator  brachio-radialis  brevior. 

Pronator  quadratus, Musculus  pronator  radii  quadratus. 

Grammatical  Xotc. — In  constructing  technical  names  of  muscles,  note  (i)  the 
agent,  and  (2)  the  descriptive  adjectives  are  in  apposition  with  musculus.  The 
thing  or  part  of  which  another  part  is  the  agent  is  in  the  genitive  case.  The 
student  will  note  that  adjectives  are  mainly  of  the  first  and  second  declensions, 
some  of  the  third  ;  sublimis  belongs  to  the  third,  so  do  not  write  it  sublimits. 

TECHNICAL  USE  OF  PREPOSITIONS. 

An  almost  unlimited  number  of  words  designative  of  relation  are  formed  by  the 
judicious  use  of  classical  prepositions.  It  will  be  noted  that  these  words,  while 
governing  case  in  the  language  from  which  they  are  taken,  cease  to  be 
prepositional  in  anatomical  nomenclature  in  the  great  majority  of  instances. 
Still  they  may  be  so  used;  and  upon  the  distinction  now  about  to  be  made  depends 
the  proper  construction  of  the  new  words  which  come  into  being  by  thousands 
by  the  simple  process  of  incorporating  classical  prepositions.  In  the  following 
cases  the  words  are  used  prepositionally,  and  written  thus  : 

1.  Iter  e  tertio  ad  quartum  ventriculum. 

2.  Processus  e  cerebello  ad  testes. 

3.  Portio  inter  duram  et  mollem. 

4.  Musculus  accessorius  ad  flexorem,  etc. 

5.  Musculus  accessorius  ad  musculum,  etc. 

In  the  majority  of  cases  the  word  is  absorbed  to  form  a  new  word,  bearing  a 
close  relation  in  location,  and  not  in  structure ;  to  the  word  into  which  it  was  incor- 
porated. The  following  examples  will  illustrate  the  process  of  forming  new- 
words  and  their  proper  writing  :  Subcostal,  intermaxillary,  infraorbital,  supra- 
orbital,  intraabdominal,  extrauterine.  Remember,  then,  this  rule  for  writing 
these  words  :  Where  they  are  prepositionally  used,  the  preposition  governs  the 
accusative  ;  where  they  are  used  in  a  corporate  capacity,  the  preposition  and  the 
qualified  word,  or  its  adjective  representative,  are  written  as  one  word. 

Inter  is  used  to  express  relation  between  anatomical  structures  having  the 
same  name.  Not  only  does  it  express  relation  in  this  sense,  but  it  also  names 
every  structure  in  the  locality  :  Intercostal  space,  muscle,  fasciae,  vessels,  and 
nerves. 

Intra — as  intrauterine,  intrapelvic,  intracranial,  intrathoracic,  intraabdominal, 
intratympanic,  intramural,  intraintestinal,  intramuscular, — means  inside  of  or  in 
the  substance  of.  Its  verbal  opposite  is  extra. 

Sub  implies  location  under,  in  the  sense  of  occupying  a  deeper  plane  :  Sub- 
cutaneous, subserous,  submucous,  subperitoneal,  subpleural,  subsynovial,  subcon- 
junctival.  It  has  no  opposite,  none  being  necessary  to  make  descriptions  of  this 
nature  more  definite.  Its  legitimate  field  of  usefulness  in  our  nomenclature 
seems  to  be  in  expressing  relations  in  the  concrete  rather  than  in  the  abstract. 
Submucous  means  a  territory  under  all  mucous  membrane  ;  subcutaneous,  under 
the  skin  everywhere,  regardless  of  location  of  skin  or  kind  of  animal.  How 
such  expressions  as  submuscular,  subosseous,  or  subgastric  would  shock  our 
conception  of  the  proper  use  of  this  word  !  Still,  such  barbarisms  as  sub- 
maxillary,  submcntal,  and  sublingual  are  sanctioned  by  usage — and  good  usage, 
too. 


FUNDAMENTAL  PRINCIPLES  OF  ANATOMY.  13 

Supra  is  limited  in  its  application  to  a  few  areas,  for  the  reason  that  it  does 
not  combine  well  to  form  euphonious  words,  and  euphony,  you  will  observe,  is 
a  potent  factor  in  determining  the  volume  of  our  anatomical  vocabulary.  The 
chief  use  of  the  term  is  in  physical  diagnosis,  where  regions  requiring  no  definite 
limitations  are  indicated  by  supra  in  combination  with  the  name  of  the  locality 
under  consideration  :  Supraorbital,  suprasternal,  supraclavicular,  suprascapular, 
suprapubic,  supratrochlear,  supratrochanteric,  supracondylar,  supragluteal,  supra- 
hyoid,  supraacetabular.  Infra  is  the  opposite,  but  can  not  with  propriety  be  used 
in  some  cases,  as  infracondylar  ridge,  since  no  such  ridge  exists. 

Juxta  has  the  specific  meaning  of  one  above  another  with  parallelism  of 
parts.  Its  use  is  confined  to  osteology  almost  wholly,  with  no  good  reason.  In 
the  vertebral  column  we  have  juxtaposition  of  bodies,  transverse,  spinous,  and 
articular  processes  ;  juxtaposition  of  laminae,  pedicles,  and  intervertebral  notches. 
Still,  for  practical  purposes,  the  biceps  and  brachialis  are  in  juxtaposition.  Usage 
determines  the  scope  of  legitimate  nomenclature. 

Pre,  as  in  preaxial,  the  opposite  of  post-axial  ;  in  presystolic ;  in  pre- 
vertebral,  in  speaking  of  the  three  great  prevertebral  gangliated  plexuses  of  the 
sympathetic  nervous  system.  The  use  of  this  word  is  limited. 

Peri. — The  prepositional  excellence  of  anatomical  nomenclature  seems  to 
culminate  in  the  word  now  under  consideration.  For  this  there  is  good  reason  : 
its  euphonious  nature  combines  with  everything  of  an  anatomical  kind,  either 
in  substantive  or  adjective  form,  and  besides  it  expresses  a  relation  comprehending 
all  other  relations — around.  Every  visible  anatomical  structure  possesses  a 
protective  coat  or  sheath,  which  surrounds  and  protects  the  same.  Many  of 
these  are  expressed  by  peri  in  combination,  as  the  following  will  show  :  Peri- 
osteum, perimysium,  periuterine,  pericardium,  peritendineum,  peridontium,  peri- 
pulmonum,  perichondrium,  perineurium,  peritoneum,  perinaeum,  periglottis, 
periorbita,  perivenal,  periproctic,  peristaltic,  perivisceral. 

In  the  course  of  your  dissection  make  a  study  of  each  technical  word  used, 
and  you  will  soon  acquire  a  habit  of  thinking  in  anatomical  terms  when  doing 
anatomical  work.  Remember  every  anatomical  region  is  occupied  by  structures, 
and  these  structures  have  names  and  relations.  If  you  learn  the  principles  on 
which  the  technical  language  of  anatomy  is  founded,  then  you  shall  have  passed 
the  first  milestone  on  your  way  to  a  medical  education.* 

THE  ANATOMICAL  TISSUES. 

In  the  dissecting-room  you  meet  normal  tissues,  as  muscle,  nerve,  and  skin, 
in  all  their  various  forms  and  combinations.  It  is  here  you  should  apply 
practically  those  things  you  have  learned  in  such  thorough  detail  in  the  histo- 
logical  laboratory.  It  is  true  you  deal  here  with  these  tissues,  not  with  the 
microscope,  but  with  the  unaided  eye  and  the  sense  of  touch.  In  the  laboratory 
you  learned  to  recognize  epithelial  tissue  in  general  and  special,  and  you  classified 
the  same  according  to  the  shape  and  strata  of  the  cell.  Here  it  is  enough  for 
you  to  remember  that  the  epithelial  tissues  cover  the  free  surface  of  the  skin  and 
mucous  membrane. 

The  Bulky  Portion  of  Your  Work  is  Made  Up  of  Muscles. — Of  these  you 
learn  origin,  insertion,  relation,  nerve-supply,  blood-supply,  investment,  and  func- 
tion. This  is  gross  anatomy.  You  must  also  remember  histologically  that 
all  muscles  belong'  to  the  muscular  tissues,  that  the  characteristic  of  these  tissues  is 

*The  technical  terms  used  in  anatomy  are  chiefly  of  Latin  derivation  ;  the  grammatical  construction 
is  purely  so.  In  view  of  the  importance  of  being  familiar  with  our  nomenclature,  I  would  recommend 
Robinson's  Latin  Grammar,  both  for  those  who  have  given  but  little  lime  to  classical  study  and  also  for 
those  who  wish  to  review  the  same. 


14  PRACTICAL  ANATOMY. 

contractility,  and  that  muscles  occur,  (i)  in  the  voluntary  form  ;  (2)  the  involuntary 
form.  You  will  be  expected  to  classify  each  muscle  according  to  the  above 
forms.  To  aid  you  in  this,  the  following  table  is  inserted  : 

TABLE  SHOWING  WHERE  INVOLUNTARY  MUSCLES  ARE  FOUND. 

Character  of  fibre  :  Smooth,  non-striated. 

1.  In  the  alimentary  canal  (oesophagus,  stomach,  intestines,  large  and  small),  and 

in  the  embryological  offspring  of  the  duodenum  (the  common  bile  duct,  the 
hepatic  ducts,  the  gall-bladder,  and  the  pancreatic  duct)  and  salivary  glands. 

2.  In  the  genito-urinary  tract  of  the  male  and  female:  the  muscular  part  of  the 

vas,  the  seminal  vesicles,  Cowper's  glands,  the  corpora  spongiosa  and 
cavernosa,  and  the  prostate  in  the  male  ;  in  the  uterus,  vagina,  Fallopian 
tubes,  round  and  broad  ligaments,  and  in  the  erectile  tissue  of  the  nipple 
and  external  genitals  of  the  female.  In  the  bladder,  urethra,  and  all  parts 
of  the  urethra  in  botJi  male  and  female. 

3.  In  the  trachea,  bronchi,  and  pleura ;    in  all  arteries,  veins,  and  lymphatics  ; 

in  the  iris,  ciliary  body,  and  eyelids  ;  in  the  skin  of  the  scrotum  ;  in  the 
hair  follicles  and  sebaceous  glands. 

4.  You  will  see  later  that  the  territory  where  you  are  to  locate  the  involuntary 

form  of  muscular  tissue  coincides  with  the  distribution  of  the  sympathetic 
nerve,  or  the  nerve  of  organic  life. 

You  Will  Find  Brain  and  Nerves. — The  structural  part  of  these  is  purely 
histological ;  still,  you  will  be  expected  to  remember  that  nerve-tissue  consists  of 
cells,  fibres,  and  neuroglia,  and  a  connective-tissue  framework.  You  will  find 
nerves,  called  sympathetic^  supplying  the  viscera  and  all  others  ;  the  ccrcbro-spinal, 
supplying  the  skin,  joints,  muscles,  and  organs  of  special  sense.  You  sJiould 
remember  that  all  brain  and  nerve  matter  belong  to  the  nervous  tissues. 

The  connective  tissues,  in  their  many  forms,  will  be  found  everywhere.  I 
wish  thus,  in  advance,  to  teach  you  where  to  find  and  how  to  classify  the  same. 
All  the  peristructures  mentioned  in  the  chapter  on  nomenclature  are  forms  of 
connective  tissue.  This  is  the  most  widely  distributed  of  all  the  tissues.  Your 
task  now  is  to  learn  to  recognize  its  forms  as  you  meet  them. 

FORMS  OF  CONNECTIVE  TISSUE  You  WILL  MEET  IN  THE  DISSECTING-ROOM. 

1.  Mucous  Form. — This  is  a  clear,  jelly-like  substance  surrounding  the  umbilical 

cord.  Ligate  this  and  see  how  easily  a  thread  cuts  through  the  same. 
This  is  the  jelly  of  Wharton  you  will  hear  about.  //  is  one  form  of  con- 
nective tissue. 

2.  Areolar  Form. — Immediately  on  removing  the  skin  you  will  notice  the  areolar 

form  of  connective  tissue.  It  is  also  called  superficial  fascia  in  this 
locality.  It  contains  a  variable  amount  of  fat..  It  is  called  areolar  mem- 
brane in  some  of  the  older  text-books.  On  separating  one  muscle  from 
another,  you  will  see  this  areolar  tissue.  Its  specific  name,  in  this  locality, 
is  intermuscular  fascia. 

3.  Cartilage  forms  of  connective  tissue  occur  in  the  trachea,  larynx,  and  external 

ear,  where  the  presence  of  this  tissue  gives  these  structures  their  strength 
and  elasticity.  You  will  find  it  completing  the  space  between  the  ribs  and 
sternum  ;  you  will  find  it  covering  the  articular  surfaces  of  bone  in 
movable  joints. 

4.  Bone  l;onn. — This  is  coextensive  with  the  osseous  skeleton.     Every  bone,  be 

it  long,  short,  flat,  irregular,  is  connective  tissue  in  this  form.  Each  bone 
is  covered,  at  its  articular  surface,  when  it  moves  upon  another  bone,  by 


FUNDAMENTAL  PRINCIPLES  OF  ANATOMY.  15 

cartilage  :  this  cartilage  is  one  form  of  connective  tissue.  Each  bone  is 
covered  by  periosteum,  except  at  the  articular  surfaces  ;  this  periosteum 
is  connective  tissue. 

5.  Elastic  Form. — In  the  interlaminar  ligaments,  or  ligamenta  subflava,  you  will 

find  a  form  of  connective  tissue,  yellowish  in  color,  and  also  dense,  elastic, 
and  strong.  You  will  find  this  as  well  in  the  epiglottis.  Wherever  you 
find  structures  possessing  (i)  elasticity,  (2)  yellowisJi  color,  as  the  aorta  and 
structures  above  mentioned,  they  owe  these  qualities  to  the  elastic  form 
of  connective  tissue. 

6.  Adipose  Form. — You  will  find  this  in  the  superficial  fascia  or  areolar  tissue 

under  the  skin  ;  in  the  great  omentum,  about  the  heart,  in  the  iliac  region 
of  the  pelvis,  and  in  the  ischio-rectal  fossa.  Remember,  fat  is  the  adipose 
form  of  connective  tissue.  This  tissue  represents  the  great  storehouse 
for  potential  energy.  The  student  who  desires  to  see  the  human  body 
in  possession  of  this  potential  energy  will  select  a  fat  subject  for  dissec- 
tion ;  while  the  student  who  desires  to  keep  his  hands  clean  will  continue 
to  clamor  for  lean  material.  If  you  intend  to  do  surgical  operations, 
remember  this  :  The  emaciated  patient  is  seldom  operated  on.  Only 
those  possessing  fat  and  vitality  are  considered  good  risks.  If  you  dissect 
a  fat  cadaver,  then  you  may  expect  to  see  man  as  he  is  in  health.  A  lean 
man  is  man  minus  fat — not  a  fair  sample. 

7.  Supporting  Form. — Dissect  any  organ,  and  you  will  find  it  covered  by  a  layer 

of  connective  tissue,  and  the  parts  making  up  the  interior  supported  by 
the  same.  Boil  a  muscle,  and  you  will  see  the  connective  tissue  interior. 
Macerate  thoroughly  a  spleen,  and  by  gentle  compression  in  warm  water 
remove  the  spleen-pulp,  and  you  will  have  remaining  the  connective  tisstie 
of  this  organ — the  supporting  form  of  connective  tissue.  The  nerve-cells  and 
nerve-fibres  are  likewise  supported  by  connective  tissue,  called  neuroglia. 

8.  Dense  Form. — This  form  you  will  find  in  tendons  and  fasciae  ;  in  the  cornea 

and  sclera ;  in  the  dense  aponeuroses  ;  in  the  strong  intermuscular  septa. 

QUERY. — How  can  a  tissue  appear  in  so  many  forms  ?  How  is  it  possible  to 
recognize  in  the  dentine  of  the  teeth  and  in  the  areolar  tissue  between  muscles  one 
and  the  same  tissue  ?  How  can  you  classify  bone  and  the  jelly  of  Wharton  in 
the  same  category  ? 

EXPLANATION. — Each  tissue  consists  of  two  constituents:  (i)  Cells,  (2)  inter- 
cellular substances.  The  former  are  products  of  the  ovum  ;  the  latter  of  the  cells 
themselves.  Each  constituent  has  a  certain  part  to  perform  in  the  organ  in  which 
the  tissue  is  found.  Upon  the  cell  depends  the  life  of  the  tissue  ;  upon  the  inter- 
cellular substance  depend  the  jelly-like  condition,  the  dentine  hardness,  the  fascial 
strength,  the  areolae  of  intermuscular  connective  tissue  and  superficial  fascia,  the 
resistance  of  muscle,  the  elasticity  of  the  ligamentum  subflavum,  the  cement  sub- 
stance of  the  epithelial  tissues  covering  the  surfaces  of  the  integument  and  the 
various  mucous  membranes. 

Homely  illustration  of  how  a  tissue  can  appear  under  so  many  different  forms 
and  still  remain  connective  tissue  :  (i)  Permit  water  to  represent  the  intercellular 
substance  ;  (2)  permit  plastcr-of -Paris  to  represent  the  cellular  element.  As  you 
mix  the  two,  the  water  will  become  more  and  more  condensed,  until  you  have 
finally  obtained  a  substance  of  bony  hardness.  The  plaster  remains  plaster, 
having  undergone  no  changes.  In  the  tissue  under  consideration  the  cellular 
element  remains  the  same  :  The  bone-cell  is  morphologically  the  same  as  the 
jelly-cell,  the  tendon-cell,  and  the  fascia-cell.  Condensation  of  the  intercellular 
substance  is  when  the  changes  have  really  taken  place. 

In   your   dissections,   when    you  find  fascia,  tendon,  bone,  cartilage,  sclera, 


i6 


PR  A  CTICAL  ANA  TOM  \ '. 


cornea,  peristructures,  supporting  structures,  dentine,  and  Wharton's  jelly,  you 
are  to  remember,  these  structures,  while  widely  varying  in  form,  all  belong  to 
the  greater  connective  tissue  family. 

RESUME  OF  ANATOMICAL  TISSUES. 

1.  Muscular   tissue,   for    voluntary    and    involuntary    contraction,    upon    which 

depend  the  aggressive  and  defensive  attitudes  of  the  body,  as  well  as 
the  movements  of  hollow  conduits  and  certain  viscera. 

2.  Nervous  tissue,  upon  which  depends  intellection,  reception  of  impression  from 

an  environment,  and  transmission  of  brain  impulses,  whether  voluntary 
or  involuntary. 

3.  Connective  tissue,  on  which  depends  strength,  framework,  and  various  invest- 

ing structures.     Common  forms  specialized  are  tendon,  ligament,  capsule, 
bone,  cartilage,  dentine,  cementum,  etc. 

4.  Epithelial  tissue,  upon  which  depend  external  and  internal  protection,  giving 

as  these  tissues  do  a  certain  resiliency  and  stability  to  the  areas  which 
they  cover,  as  the  skin  and  mucous  membranes. 


/$W  ofcompressed 
cotfon  reareseafint 


sheath. 


Nerve 


Artery 


Vein 


FIG.  i. — DISPLACEMENT  OF  COTTON  BY  GROW- 
ING PLANTS. 


Meuro  venous  septum 
Neuro  •  arterial  septum- . 

FIG.  2. — CONNECTIVE  TISSUE  DISPLACED  BY 
THE  ARTERY,  NERVE,  AND  VEIN;  THE 
CONNECTIVE  TISSUE  LEFT  BETWEEN  THE 
ARTERY  AND  NERVE  AND  BETWEEN  THE 
NERVE  AND  VEIN  ARE  Two  SEPTA. 


Rationale  of  the  formation  of  anatomical  sheaths,  tunics,  togas,  cap- 
sules, and  all  the  peristructures  referred  to  and  enumerated  in  the  section  on 
anatomical  nomenclature. 

In  your  dissections  you  will  meet  the  capsules  of  glands  and  the  sheaths  of 
vessels.  Where  an  artery,  vein,  and  nerve  are  in  the  same  sheath,  they  will  be 
separated  from  each  other  by  a.  septum.  In  your  first  dissection  you  will  be  dis- 
appointed at  the  frail  condition  of  these  sheaths — at  their  lack  of  organization. 
You  will  expect  to  find  the  sheath  of  an  artery  resemble  a  piece  of  heavy  cloth 
sewed  tightly  about  the  trunk  of  a  tree  ;  your  chagrin  will  be  manifest  when 
you  find  it  resembles  more  the  investment  of  straw  given  tender  shrubs  to  pre- 
vent depredations  of  rodents  in  our  parks.  As  any  attempt  to  remove  the  pro- 
tective from  the  tree  would  result  in  the  complete  destruction  of  the  protective,  as 
you  removed  straw  after  straw,  so,  likewise,  when  you  attempt  to  disen- 
sheath  a  vessel  you  arrive  at  the  vessel,  but  the  sheath  has  disappeared.  Re- 
member, then,  sheaths  arc  actual  entities,  and  their  architecture  is  adapted  to  the 
needs  and  requirements  of  the  vessel  ensheathed,  just  as  the  cobweb  is  architect- 
urally suited  to  the  needs  of  the  spider;  still,  when  you  molest  the  latter  or 
attempt  to  dissect  the  former,  the  result  is  the  same — each  almost  completely 
disappears,  such  is  the  delicacy  of  their  respective  material. 


FUNDAMENTAL  PRINCIPLES  OF  ANATOMY.  17 

For  the  sake  of  gaining  a  conception  of  the  architecture  of  sheaths  and  the 
rationale  of  their  formation  by  displacement  of  connective  tissue,  let  the  follow- 
ing explanation  be  studied  :  Figure  I  represents  a  pot  of  earth  in  which  various 
seeds  have  been  planted ;  the  pot  is  covered  with  a  layer  of  absorbent 
cotton,  and  exposed  to  the  sun  and  rain.  In  time  the  cotyledons  begin  to 
peep  through  the  cotton ;  as  each  becomes  larger  in  diameter,  it  displaces 
more  cotton.  As  the  cotton  displaced  by  the  growing  plant  may  represent  the 
sheath  of  the  plant,  so,  in  like  manner,  to  aid  the  memory,  let  us  compare  a 
growing  artery,  bone,  muscle,  nerve,  or  gland  surrounded  by  connective  tissue 
(which  represents  the  cotton  in  the  simile  of  the  growing  plant)  to  the  plant. 
The  connective  tissue  would  be  displaced  as  the  anatomical  structure  became 
thicker,  and  this  displaced  tissue  we  call  the  sheath,  capsule,  tunic,  toga,  or 
peristructure. 

Now,  by  the  same  process  account  for  periosteum,  perimysium,  perineurium, 
and  all  peristructures  and  capsules. 

PERIOSTEUM  AND  ITS  FUNCTIONS. — Periosteum  is  the  anatomical  investment 
of  bone.  It  covers  all  the  bone  except  the  articular  surfaces.  It  is,  as  you 
must  demonstrate  on  your  dissection,  most  intimately  adherent  to  those  parts  of 
the  bone  having  the  greatest  number  of  irregularities.  Its  functions  are  as 
follows  : 

1 .  Osteogenetic,  for  it  makes  bone  grow  in  thickness. 

2.  Protective,  since  it  hinders  progress  of  contiguous  inflammation. 

3.  Attaclnnental,  since  it  gives  attachment  to  muscles. 

4.  Nutritive,  since  it  feeds  the  bone  with  blood. 

5.  LAgamentous,  since  it  forms  all  capsular  ligaments. 

6.  Retentive,  since  it  tends  to  retain  ends  of  broken  bones. 

EMINENCES,  DEPRESSIONS,  AND  SURFACES  OF  BONE  are  determined  in  shape 
by  the  muscles  associated  therewith,  and  take  the  name  of  the  muscle.  You  are 
to  look  on  muscular  traction  as  the  factor  that  determines  the  size  of  an  eminence 
or  the  depth  of  a  fossa.  In  fact,  the  surfaces  of  bone  are  named  according  to 
the  occupant.  In  a  given  bone,  as  the  humerus,  name  the  articular  surfaces 
according  to  the  occupants:  (i)  Scapular;  (2)  radial;  (3)  ulnar.  Name  the 
surfaces  according  to  the  muscles.  The  posterior  surface  has  an  upper  and  a 
lower  tricipital  surface,  corresponding  to  the  humeral  heads  of  the  triceps,  etc. 
Bicipital  tuberosity,  iliac  fossa,  gluteal  ridge,  deltoid  impression,  are  instances. 
You  will  observe  that  this  rule  is  not  always  observed  ;  still  the  value  of  the  rule 
is  no  less. 

ANATOMICAL  WEAK  POINTS  comply  with  two  conditions:  (i)  A  location  in 
the  continuity  of  the  structure  where  there  is  a  sudden  abrupt  cJiange  in  the 
direction.  (2)  A  functional  area,  as  between  skin  and  mucous  membrane,  as 
where  the  small  intestine  opens  into  the  large.  In  these  localities  fractures  occur 
in  bone,  aneurisms  in  arteries,  morbid  growths  at  muco-cutaneous  areas.  In 
your  dissection  bear  these  areas  in  mind.  Look  for  intussusceptions  at  the 
weak  points  in  the  colon  ;  for  fractures  at  the  necks  of  bones,  etc. 

ANATOMICAL  ROOTS  are  places  uncovered  by  serous  membrane,  in  connection 
with  viscera,  where  the  vessels,  nerves,  and  conduits  enter  to  carry  on  (i)  the 
functional  activity  and  (2)  the  nutritive  activity  of  the  organ.  In  your  dissection 
you  will  give  special  study  to  the  root-structures  of  the  heart,  lung,  liver,  spleen, 
kidney,  intestine,  ovary,  testicle,  etc.  The  functional  activity  is  represented  by 


i8 


PRACTICAL   ANATOMY. 


what  the  organ  does  for  the  body  in  general  ;  the  nutritive  activity  by  what  the 
organ  does  for  its  own  nutrition.  The  nutrient  artery  to  organs  is  accompanied  by 
sympathetic  nerves,  which  regulate  the  supply  of  blood  each  organ  shall  receive. 

ANATOMICAL  ANTAGONISM  IN  MUSCLES  necessitates  a  consequent  antagonism  in 
the  nerves  that  supply  these  muscles,  hence  you  will  understand  the  meaning  of 
flexor,  extensor,  abductor,  and  adductor  nerves.  The  very  nature  of  logical 
antagonism  implies  a  degree  of  equality  in  length,  weight,  strength,  and  vantage 
for  origin  and  insertion.  At  the  hip,  flexors,  extensors,  abductors,  and  adductors 
are  seen.  The  antagonistic  nerves  are  the  anterior  crural,  the  great  sciatic,  the 
obturator,  and  the  gluteal. 

SHAPE  OF  MUSCLES  AN  INDEX  TO  THE  PLACE  WHERE  THE  MUSCLE  RECEIVES 
ITS  NERVE-SUPPLY. — I  desire  you  to  study  carefully  the  following  drawings,  and 
in  your  dissection  you  must  faithfully  determine  the  general  shape  of  the  muscle 
and  trace  out  the  nerve  thereto. 

i.  Triangular  Muscles. — The  pectorales  major  and  minor,  the  supra-  and  infra  - 
spinati,  the  subscapularis,  the  deltoid,  the  gluteals,  the  pyriformis,  and 
the  obturators  are  examples  ;  take  their  nerve-supply  near  the  apex. 


FIG.  3. — TRIANGULAR.          FIG.  4. — QUADRANGULAR.        FIG.  5. — FUSIFORM.     FIG.  6.  —  Ci.ri;i:i  i>. 


2.  Quadrate  Muscles. — The    pronator    quadratus,    the    brachialis    anticus,    and 

multifidus  spinae  are  good  examples  ;  take  their  nerve-supply  near  the 
centre. 

3.  Fusiform  Muscles. — Take  their  nerve-supply  near  the  middle.     This,  as  the 

biceps,  is  the  same  as  No.  2,  compressed  at  the  ends. 

4.  Clubbed  Muscles. — This  includes  a  large  number,  as  those  taking  origin  from 

the  outer  and  inner  humeral  condyles  take  their  nerve-supply  early.  In 
your  work  notice  how  very  early  the  median  gives  off  branches  to  supply 
muscles  of  this  type. 

5.  Scrrati  muscles  and  those  arising  by  more  or  less  pronounced  digitations,  as 

the  serrati  superior  and  inferior  posticus,  the  diaphragm  and  the  planiform 
muscles  of  the  abdominal  walls,  seem  to  conform  to  the  type  of  triangu- 
lar muscles,  taking  their  nerve-supply  near  the  apices  of  the  digitate 
origins  ;  still,  if  the  nerves  are  traced  out,  they  will  be  found  to  approach 
the  centre  and  conform  to  the  quadrate  type. 

Remember,  this  tracing  out  of  nerves  belongs  to  macroscopic  anatomy.  To 
gain  an  idea  of  the  manner  in  which  the  ultimate  tissue  is  innervated,  you  must 
study  up  motorial  end  plates  in  physiology  and  histology.  The  only  object  in 


FUNDAMENTAL  PRINCIPLES  OF  ANATOMY.  19 

introducing  the  subject  of  shape  of  a  muscle  as  an  index  to  the  nerve-supply 
entrance  is  to  impress  the  necessity  of  tracing  out,  as  far  as  possible,  in  your  dis- 
section the  branches  of  the  nerves  ;  possibly  the  scheme  introduced  may  aid  the 
memory. 

HILTON'S  LAW  :  Nerve  trunks  that  supply  muscles  that  move  a  joint  supply 
the  joint  acted  upon  with  articular  brandies  ;  they  also  supply  the  skin,  covering 
the  fullest  insertion  of  the  muscle.  Given,  then,  the  number  of  antagonistic 
groups  of  muscles,  you  are  by  this  rule  able  to  know  the  source  from  which  the 
joint  is  innervated. 

ANATOMICAL  APPOSITION  Is  NOWHERE  FOUND. — In  dissecting  in  any  region  of 
the  body  bear  this  in  mind.  Structures  arc  a  fa  ays  disjunctively  connected  by  a 
layer  of  connective  tissue.  Found  between  muscles,  it  is  called  areolar  or  inter- 
muscular  connective  ;  beneath  the  pleura,  subpleural  ;  beneath  the  peritoneum, 
subperitoneal  ;  beneath  mucous  membrane,  submucous  ;  beneath  the  periosteum, 
subperiosteal.  Notice  the  mortar  between  the  bricks  in  a  wall  ;  this  corresponds 
to  connective  tissue  in  anatomy. 

DISSECTING  Is  THE  ART  OF  DIVIDING  THE  CONNECTIVE  TISSUE  THAT  INTER- 
VENES BETWEEN  ADJACENT  STRUCTURES,  and  the  division  must  be  made  in  such  a 
manner  as  to  do  no  violence  to  anatomical  compounds, — their  nerve-supply,  their 
blood-supply,  their  excretory  ducts,  their  capsules,  and  their  anatomical  relations. 

FANCIFUL  NAMES  FOR  MUSCLES,  names  founded  on  some  one  dominant  idea,  are 
frequently  met.  It  is  to  be  regretted  that  our  nomenclature  could  not  have  been 
founded  on  the  idea  of  function  throughout.  Note  here  that  the  substantive, 
imtscitlns,  while  seldom  expressed  in  our  texts,  is  afaars  implied.  The  following 
will  show  you  some  of  the  names  of  muscles  founded  on  fanciful  ideas,  and  also 
the  full  name  as  it  should  appear  if  founded  on  the  idea  of  function  : 

FANCIFUL  NAMES.  PHYSIOLOGICAL  NAMES. 

Sartorius  (tailor),   ....  Musculus  extensor  tibialis  et  adductor  femoris. 
Rhomboideus  (geom.),   .    .  Musculus  levator  scapulas  rhomboideus. 
Transversals  (direct.),  .    .  Musculus  compressor  abdominis  transversalis. 

Recius  (geom.) Musculus  flexor  thoracis  rectus. 

Pyramida/is(geom.).  .    .    .  Musculus  tensor  lineas  albae  pyramidalis. 

Vastus  Externus,    ....  Musculus  extensor  vastus  externus. 

External  Oblique,   ....  Musculus  compressor  abdominis  obliquus  externus. 

Serratus  Magnus,    ....  Musculus  depressor  scapulae  serratus  magnus. 

Quadratus  Lumborum,     .  Musculus  flexor  spins  lateralis  quadratus  lumborum. 

Latissimus  Dorsi,   ....  Musculus  abductor  brachii  latissimus  dorsi. 

Longissinms  Dorsi,     .    .    .  Musculus  extensor  spinse  longissimus  dorsi. 

ORBICULAR  MUSCLES  AND  SPHINCTER  MUSCLES. — You  will  find  the  above 
terms  often  used  interchangeably.  The  important  areas  occupied  by  these 
muscles  make  the  majority  of  the  same  of  prime  interest  to  the  general  surgeon, 
the  genitp-urinaiy  specialist,  the  gynaecologist,  the  obstetrician,  the  oculist, 
the  laryngologist,  the  rectal  specialist,  the  patient.  Still,  no  rational  classification 
of  these  muscles  exists.  At  the  present  all  orbiculars  are  sphincters,  but  not  all 
sphincters  are  orbiculars,  as  the  following  table,  founded  on  usage,  will  show  : 

SYNONYMOUS  USAGE. 

Orbicularis  oris Sphincter  oris. 

Orbicularis  ani External  sphincter  ani. 

Orbicularis  palpebrarum, Sphincter  palpebrarum. 


2o  PRACTICAL  ANATOMY. 

UNIVERSAL  USE  OF  SPHINCTER. 

Musculus  sphincter  vaginae.  Musculus  sphincter  iridis. 

Musculus  sphincter  urethrae.  Musculus  sphincter  ilei. 

Musculus  sphincter  prostatas.  Musculus  sphincter  gulae. 

Musculus  sphincter  cesophagei.  Musculus  sphincter  vesicae. 
Musculus  sphincter  laryngis. 

As  the  following  comparison  will  show,  there  is  no  good  reason  for  confusion 
of  terms  and  an  annoying  interchange  between  orbicular  muscles  and  sphincter 
muscles.  Such  is  usage.  » 

Summary  of  Differences  Between  Orbiculars  and  Sphincters  : 

Orbicular s. 

1.  The  orbiculars  are  supplied  by  spinal  nerves. 

2.  The  orbiculars  are  all  voluntary. 

3.  The  orbiculars  are  all  dermal  muscles. 

4.  The  orbiculars  are  at  muco-cutaneous  margins. 

5.  The  orbiculars  move  rapidly. 

6.  The  orbiculars  have  parietal  blood-supply. 

7.  The  orbiculars  are  very  sensitive  to  pain. 

8.  They  refer  their  pain  to  place  of  irritation. 

9.  They  report  pain  foudroyantly. 

10.  Their  nerve-supply  is  somatic — never  sympathetic. 

11.  When  lacerated,  they  repair  slowly. 

12.  They  are  synonymous  for  sphincters  in  three  cases  only. 

Sphincters. 

1.  Sphincters  are  supplied  by  the  sympathetic. 

2.  They  are  all  involuntary — unstriped  fibre. 

3.  They  are  not  dermals,  but  viscerals. 

4.  They  are  never  at  muco-cutaneous  areas. 

5.  They  always  move  slowly. 

6.  They  have  visceral  blood-supply. 

7.  They  are  not  very  sensitive  to  pain. 

8.  They  refer  pain  to  somatic  areas. 

9.  Their  own  report  of  pain  is  dull  and  slow. 

10.  Their  nerve-supply  is  sympathetic. 

1 1.  When  lacerated,  they  repair  readily. 

The  reader  is  referred  to  reflexes  along  somatic  and  sympathetic  lines  in  the 
dissection  of  the  female  pelvis. 

TIic  ('tents. 

This  would  seem  to  be  the  most  fully  grown  and  fully  developed  structure 
among  the  organs  having  sphincteric  openings.  Its  proper  sphincters  aie 
known  as  the  os  intcnntm  and  os  cxternum.  It  complies  in  every  way  to  eleven 
points  characteristic  of  sphincters. 

GEOMETRICAL  TERMS  AND  FIGURES. — You  will  have  much  descriptive  usage 
along  mathematical  lines.  This  always  aids  the  memory,  for  it  appeals  to  the 
basis  of  every  one's  education. 

The  axilla  has  base,  apex,  angles,  and  boundaries. 

The  neck  has  roof,  floor,  boundaries,  and  triangles. 

Tlic  nasal  fossa  has  roof,  floor,  walls,  and  openings. 

The  orbit  has  roof,  floor,  base,  apex,  angles,  and  walls. 


FUNDAMENTAL  PRINCIPLES  OF  ANATOMY.  21 

77/6'  mouth  has  roof,  floor,  sides,  openings,  dental  arches. 

The  tympanum  has  roof,  floor,  and  four  walls. 

Hunter's  canal  has  roof,  floor,  boundaries,  and  extremities. 

Scarpds  triangle  has  roof,  floor,  base,  apex,  boundaries. 

The  iscldo-rcctal  fossa  has  base,  apex,  walls,  sacral  and  pubic  ends. 

The  thorax  has  apex,  base,  anterior,  posterior,  and  lateral  walls. 

Inguinal  canal  has  rings,  roof,  floor,  and  two  walls. 

Popliteal  space  has  roof,  floor,  extremities,  and  boundaries. 

SUBSTANTIVE  ADJECTIVES. — These  are  so  frequently  used  that  I  wish  the 
student  early  to  learn  to  supply  the  missing  substantive,  not  only  in  the  case  of 
muscles,  as  referred  to  in  nomenclature,  but  also  in  the  case  of  arteries,  veins, 
nerves,  and  lymphatic  glands.  In  social  life,  after  long  and  thorough  acquaintance 
with  your  fellows,  you  justifiably  dub  your  friends  John,  James,  and  the  like,  the 
while  mindful  of  the  full  baptismal  name  ;  these  liberties  of  address  you  would 
consider  improper  in  addressing  comparative  strangers.  Likewise  in  anatomy 
you  speak  of  structures  as  follows  : 

i.  A  FRIEND.  2.  A  STRANGER. 

The  radial  artery  or  vein Arteria  radialis  or  vena  radialis. 

The  ulnar  artery  or  vein, Arteria  ulnaris  or  vena  ulnaris. 

The  brachial  artery  or  vein, Arteria  brachialis  or  vena  brachialis. 

The  femoral  artery  or  vein Arteria  femoralis  or  vena  femoralis. 

The  hepatic  artery  or  vein, Arteria  hepatica  or  vena  hepatica. 

The  splenic  artery  or  vein, Arteria  splenica  or  vena  splenica. 

The  vertebral  artery  or  vein,    ....  Arteria  vertebralis  or  vena  vertebralis. 
The  mesenteric  artery  or  vein,  ....  Arteria  mesenterica  or  vena  mesenterica. 

The  lingual  artery  or  vein Arteria  lingualis  or  vena  lingualis. 

The  facial  artery  or  vein, Arteria  facialis  or  vena  facialis. 

Lymphatic  Glands. 

Cervical  gland, Glandula  lymphatica  cervicalis. 

Mesenteric  gland, Glandula  lymphatica  mesenterica. 

Inguinal  gland, Glandula  lymphatica  inguinalis. 

Axillary  gland, Glandula  lymphatica  axillaria. 

Epitrochlear  gland, Glandula  lymphatica  epitrochlearis. 

Nerves. 

Radial, Nervus  radialis. 

Ulnar Nervus  ulnaris. 

Femoral, Nervus  femoralis. 

Lingual, Nervus  lingualis. 

Facial, Nervus  facialis. 

Circumflex Nervus  circumflexus. 

Great  sciatic, Nervus  sciaticus  magnus. 

Sympathetic, Nervus  sympatheticus. 

Remember,  arteries,  nerves,  veins,  lymphatics,  and  muscles  are  spoken  of, 
the  country  over,  in  the  adjective  abbreviated  form  by  those  who  know  what 
they  are  talking  about ;  you,  however,  are  not  to  speak  of  these  structures  in 
the  abbreviated  form  until  you  are  familiar  with  the  classical  name.  After  such 
knowledge  has  been  acquired,  then  ahvays  be  governed  by  usage. 

LAW  OF  PROJECTILES. — In  anatomy  and  physiology,  in  obstetrics  and  surgery, 
in  therapeutics  and  chemistry,  we  must  frequently  invoke  a  reason  for  the  location 
of  a  nerve  or  vessel  ;  for  the  direction  taken  by  pus  or  a  bullet ;  for  a  misplaced 
foetal  head  in  utero  ;  or  for  the  tracts  pursued  by  pain  and  motion,  when  these 
manifestations  are  far  removed  from  their  logical  locality.  The  above — pain,  pus, 


22  PRACTICAL  ANATOMY. 

foetal,  ovoid,  bullet,  and  motion — are  all  projectiles,  and  act  in  accordance  with  this 
law  :     A  projectile  follows — 

1 .  The  point  of  least  resistance. 

2.  The  line  of  greatest  traction. 

3.  The  resultant  of  the  two. 

Grooves  Transmitting  Vessels  and  Nerves,  and  an  Application  of  the 
Law  of  Projectiles. — You  may  be  surprised,  in  your  subsequent  dissection 
work  on  the  cadaver,  to  find  arteries  and  nerves,  as  a  rule,  in  grooves.  This, 
however,  is  the  case,  and  you  are  to  name  the  groove  according  to  the  name  of  the 
artery,  except  in  those  cases  where  the  channel  so  expands  as  to  be  of  great 
surgical  importance,  in  which  case  the  space  would  seem  rather  to  give  its  name 
to  the  vessel.  You  are  to  learn  and  study  these  grooves  according  to  roof,  floor, 
boundaries,  and  contents.  If  you  can  do  this  on  the  cadaver,  then  you  will  be 
competent  to  do  the  same  thing  on  a  patient.  You  ask,  Why  do  these  structures 
occupy  grooves  ?  Philosophy  answers,  projectiles  folloiv  the  line  of  least  resistance. 

APPLICATION  OF  THE  LAW  OF  PROJECTILES  IN  THE  CASE  OF  PAIN  REMOTE 
FROM  PLACE  OF  INJURY. — The  cranio-spinal  nerves  are  called  somatic.  Nerves 
that  supply  the  thoracic,  abdominal,  and  pelvic  viscera  are  called  sympatJietic  or 
visceral. 

A  burn  on  the  surface  of  the  body  is  painful.  The  pain  is  violent  and  quickly 
reported  to  the  brain.  No  one,  not  even  the  physician,  is  in  doubt  as  to  the 
location  of  the  pain.  The  individual  nerve-fibres  of  somatic  nerves  are  of  large 
calibre,  and  the  course  of  the  same  is  not  interrupted  by  ganglia.  These  condi- 
tions would  seem  to  favor  rapid,  direct  transmission  of  both  pain  and  motion. 

In  cancer  of  the  stomach  the  pain  is  in  the  abdominal  walls.  In  entcralgia  the 
pain  is  in  the  region  of  the  umbilicus.  In  renal  colic  the  pain  is  in  the  end  of  the 
penis.  In  ovaritis  the  pain  is  in  the  back,  chest,  scalp,  and  upper  or  lower  extremities. 
In  each  instance  above  cited  the  pain  is  referred  to  a  territory  supplied  by  cerebro- 
spinal  and  not  by  sympathetic  nerves.  In  each  instance  the  pain  originates  in 
a  territory  supplied  by  sympathetics.  In  each  instance  pain  is  a  projectile, 
and  must  obey  the  universal  law  of  projectiles.  It  is,  then,  the  duty  of  physician 
and  student  alike  to  trace  out  the  anatomical  tracks  by  which  the  pain  rationally 
travels.  You  will  note,  further,  that  in  each  case  above  cited  the  pain  was  referred 
or  reflected  to  the  skin  via  those  somatic  nerves  which  had  their  origin  nearest 
the  sympathetic  plexuses  from  which  the  affected  organs  drew  their  sympathetic 
nerve-supply.  The  only  rational  conclusion  then  is,  it  would  seem,  this  :  Pain 
is  referred  to  somatic  areas  because  these  nerves  are  so  constructed  as  to  offer 
minimal  resistance  to  the  transmission  of  pain.  In  other  words,  projectiles  follow 
the  line  of  least  resistance.  In  your  dissections  you  will  be  expected  to  find  the 
communications  betiveen  somatic  and  sympatJietic  nerves. 

FASCIA  (PLURAL);  FASCIA  (SINGULAR). 

The  word  "fascia"  will  probably  occur  more  frequently  in  your  anatomical 
reading  than  any  other  word.  The  term  means  a  sack  or  bundle,  but  any 
amount  of  derivation,  any  amount  of  description  in  books,  will  give  no  adequate 
idea  of  the  application  of  the  word  fascia  in  all  its  various  forms  as  met  in  dissect- 
ing. The  structure,  to  be  understood  and  appreciated,  must  be  seen  and  studied 
on  the  cadaver.  I  submit  this  little  outline  on  fascia,  hoping  thereby  to  give  the 
student  a  working  basis  for  intelligent  dissection. 

There  are  two  grand  divisions  of  fasci;u  : 


FUNDAMENTAL  PRINCIPLES  OF  ANATOMY.  23 

1.  The  superficial  fascia,  found  under  the  skin  in  every  region  of  the  body. 
This  is  also  called  in  histology  the  areolar  form  of  connective  tissue. 

2.  The  deep  fascia  or  fascia  profunda  has  the  following  characters  : 

(1)  It  is  dense,  heavy,  and  strong  in  some  places  ;  weak  in  other  places. 

(2)  It  is  attached  to  bone  in  subcutaneous  areas. 

(3)  It  has  perforations  for  cutaneous  vessels  and  nerves. 

(4)  It  is  attached  to  all  eminences  of  bone  in  the  vicinity  of  joints. 

(5)  It  is  a  dense  form  of  connective  tissue. 

(6)  It  receives  many  different  names  in  different  localities. 

You  will  study  the  following  description,  and,  if  necessary,  refer  to  it  frequently 
in  your  dissections. 

SPECIAL  NAMES  AND  SPECIAL  FUNCTIONS  OF  FASCIA  PROFUNDA. — (i)  In  the 
upper  extremity  ;  (2)  in  the  lower  extremity ;  (3)  in  association  with  muscles  ;  (4) 
in  surgical  areas  ;  (5)  forming  intemnuscular  septa. 

In  tlie  upper  extremity  the  deep  fascia  occurs  as  : 

1.  Anterior  annular  ligament  lies  in  front  of  the  carpus.      Under  this  pass  the 
median  nerve,  flexor  sublimis  digitorum,  flexor  profundus  digitorum,  flexor  longus 
hallucis.     This  is  ^  of  an  inch  thick,  extending  from  the  os  trapezium  on  thumb 
side  to  the  pisiform  bone  and    unciform  process  of  the  unciform  bone  on   ulnar 
side.      It  is  continuous   below  with  the  palmar  fascia,  and  above  with  the  deep 
fascia  covering  the  muscles.      Its  function  is  to  bind  down  the  structure  under  it. 

2.  Posterior  annular  ligament  is  behind  the  carpus.      Under  it  pass  the  three 
extensors  of  the  thumb,  the  three  carpal  extensors,  the  extensor  indicis,   the 
extensor   minimi   digiti,    the    extensor  communis  digitorum.      It   is    continuous 
above  with  the  deep  fascia  covering  the  muscles,  below  with  the  fascia  of  the 
back  of  the  hand.     It  has  seven  synovial  compartments. 

3.  Palmar  fascia  has  an  outer  part,  the  thenar,  covering  the  thenar  eminence  ; 
an  inner  part,  covering  the  hypothenar  eminence  ;  a  middle  part,  covering  the 
great  distributing  area  to  the  fingers  ;  a  neuro-vasal  area,  in  which  are  the  median 
nerve,  the  ulnar  nerve,  and  the  superficial  palmar  arch.      It  is   continuous  above 
with  the  annular  ligament,  below  with  the  ligamenta  vaginales  ;  laterally,  with 
the  fascia  dorsalis. 

4.  Dorsal  fascia  is  on  the  dorsum  of  the  hand.      It  binds  the  tendons  down 
and  holds  them  together.      It  is  continuous  above  with  the   annular  ligament ; 
below,  with  the  extensor  tendons.      It  is  called  fascia  dorsalis  mantis,  in  contra- 
distinction to  the  fascia  dorsalis  pedis. 

Ligamenta  Taginales  form  dense  sheaths  for  the  flexor  tendons  of  the  fingers. 
They  are  lined  with  synovial  membrane  called  theca.  The  thecne  terminate  in 
thecal  culs-de-sac  for  all  the  fingers  between  the  thumb  and  little  finger  op- 
posite the  metatarso-phalangeal  articulation.  The  theca;  for  the  little  finger 
and  thumb  terminate  above  in  the  general  synovial  sac  under  the  anterior  annular 
ligament.  Very  often  the  thecae  for  the  little  finger  and  thumb  terminate  as  do 
the  other  three  digits. 

SPECIAL  NAMES  AND  SPECIAL  FUNCTIONS  FOR  THE  DEEP  FASCIA  OF  THE 
LOWER  EXTREMITY  : 

Fascia  lata,  the  deep  fascia  on  the  front  of  the  thigh.  It  has  an  iliac  and 
a  pubic  part,  separated  by  the  saphenous  opening.  It  is  continuous  above  with 
Poupart's  ligament ;  below,  with  eminences  about  the  knee.  It  is  very  dense 
and  strong. 

Ilio-tibial  band  is  in  reality  the  aponeurotic  insertion  of  the  tensor  vaginae 
femoris  muscle.  The  fascia  or  band  is  inserted  into  the  eminences  about  the 
outer  part  of  knee. 

Anterior  annular  ligament  extends  from  malleolus  to  malleolus.  Under  it  are 
found  the  tibialis  anticus,  the  extensor  proprius  hallucis,  the  extensor  longus  digi- 


24  PRACTICAL  ANATOMY. 

torum,  the  peroneus  tertius,  the  anterior  tibial  artery  and  nerve.  It  is  continu- 
ous above  with  the  deep  fascia  ;  below,  with  the  dorsal  fascia. 

External  annular  ligament  extends  from  outer  malleolus  to  os  calcis.  Under 
it  are  the  peroneus  longus  and  peroneus  brevis.  On  it  rest  the  short  saphenous 
vein  and  nerve. 

Internal  annular  ligament  extends  from  inner  malleolus  to  os  calcis.  Under 
it  are  the  tibialis  posticus,  the  flexor  longus  digitorum,  a  sheath  containing  the 
posterior  tibial  nerve,  artery,  and  veins  ;  behind  this  sheath  is  the  tendon  of  the 
flexor  longus  hallucis. 

Dorsal  fascia — fascia  dorsalis  pedis — is  on  the  back  of  the  foot.  It  covers 
the  extensor  muscles  and  the  dorsalis  pedis  artery.  It  is  continuous  above  with 
the  annular  ligament ;  below,  with  the  extensor  tendons  to  the  toes. 

Plantar  fascia  is  on  the  sole  of  the  foot.  It  has  three  parts, — an  outer  or 
hypothenar,  an  inner  or  thenar  portion,  a  central  portion.  These  cover  three 
muscles,  forming  the  first  layer.  Behind,  it  is  attached  to  the  os  calcis  ;  in  front,  it 
is  continuous  with  the  ligamenta  vaginales. 

Liganicnta  vaginales  are  strong  sheaths  for  the  flexor  tendons.  They  are 
lined  by  synovial  membrane.  These  thecae  all  terminate  in  thecal  culs-de-sac 
i .  5  inches  above  the  toe-clefts. 

DEEP  FASCIA  ASSOCIATED  WITH  MUSCLES.— The  location  of  some  muscles  is 
such  that  their  action  extraordinarily  develops  the  fascial  investment  on  one 
surface  of  the  muscle.  This  is  always  at  the  expense  of  the  fascia  on  the  other 
side  of  the  muscle.  The  fascia  then  takes  the  name  of  the  muscle,  as  follows  : 

1 .  Masseter  muscle,  masseteric  fascia. 

2.  Temporal  muscle,  temporal  fascia. 

3.  Deltoid  muscle,  deltoid  fascia. 

4.  Supraspinous  muscle,  supraspinous  fascia. 

5.  Infraspinous  muscle,  infraspinous  fascia. 

6.  Obturator  interims  muscle,  obturator  fascia. 

7.  Iliac  muscle,  iliac  fascia. 

8.  Transversalis  muscle,  transversalis  fascia. 

9.  Pectoralis  major  muscle,  pectoral  fascia. 
10.  Biceps  muscle,  bicipital  fascia. 

DEEP  FASCIA  IN  SURGICAL  AREAS. —  I.  The  deep  fascia  helping  to  form  the 
base  of  the  axilla  is  called  axillary,  suspensory.  It  is  strong,  continuous  in  front 
with  the  pectoral  ;  externally,  with  the  brachial  ;  posteriorly,  with  the  fascia  of 
the  latissimus  dorsi. 

2.  Pelvic  fascia  has  the  following  names  according  to  muscle,  function,  etc.  : 
Iliac,  iliac  muscle  ;   psoas,  psoas  muscle  ;   obturator,  obturator  internus  muscle  ; 
anal   fascia,   levator   ani   muscle  ;  pubo-prostatic,  anterior  ligament  of  bladder ; 
recto-vesical ;  pelvic  white  line  ;  inner  layer  of  the  triangular  ligament. 

3.  Popliteal  fascia  helps  to  form  the  roof  of  the  popliteal  space.      It  possesses 
some  transverse  muscular  fibres,  by  which  the  resiliency  of  the  fascia  is  kept  up 
in  forced  extension  of  the  leg.     It  is  perforated  by  the  short  saphenous  vein  and 
nerve. 

4.  Cubital  fascia  covers  the  cubital  fossa  in  the  retiring  angle  of  the  elbou . 
It  covers  the  median  nerve,  the  tendon  of  the  biceps,  the  brachial  artery  and  its 
terminals,  the   radial   and    ulnar,  and  some   of  their  branches.      It  is  also  called 
bicipital  fascia,  semi  lunar  fascia,  and  falciform  fascia. 

DEEP  FASCIA  FORMING  INTERMUSCULAR  SEPTA. —  i.  The  group  of  muscles  on 
the  front  of  the  thigh  is  separated  from  the  adductor  group  internally,  and  from 
the  flexor  group  posteriorly ;  also,  the  flexor  group  is  separated  from  the 
adductor  group. 

2.    The  pcrotici  muscles  are  separated  from  the  flexors  behind  and  the  group 


FUNDAMENTAL  PRINCIPLES  OF  ANATOMY.  25 

on   the  anterior  surface   of  the  tibia  and  fibula  in  front.      The  superficial  group 
behind  is  separated  from  the  deep  group. 

3.  The  radial  group  of  the  forearm  is  separated  from  the  flexors  in  front  and 
the  extensors  behind.      The  superficial  is  separated  from  the  deep  group  on  the 
anterior  part  of  the  forearm. 

4.  Groups  of  muscles,  acting  in  harmony  to  discharge  some  one  physiological 
function,  form  a  musculature.      Adjacent  musculatures  are  always  separated  by 
septa  of  deep  fascia.     Each  musculature  has  its  own  nerve-supply.     Fascial  septa 
are  always  attached  to  the  bone,  being  continuous  there  with  the  periosteum. 

APONEUROSIS. — The  term  aponeurosis,  in  the  plural,  aponeuroses,  applies  to 
dense,  strong  fascia,  in  localities  where  the  action  of  the  fascia  is  intimately  asso- 
ciated in  more  than  a  secondary  manner  with  that  of  a  muscle.  You  will  find 
the  aponeurosis  of  the  diaphragm,  of  the  internal  and  external  oblique  and  trans- 
versalis  muscles  of  the  abdomen,  the  occipito-frontal  aponeurosis,  the  lumbar, 
pharyngeal,  and  vertebral  aponeuroses.  In  these  places  this  structure  forms 
either  an  integral  part  of  the  muscle  itself,  or  constitutes  the  main  structure  in 
the  region  in  which  it  is  found.  The  terms  aponeurosis  of  investment  and  inser- 
tion refer  to  the  structure  as  forming  either  a  cover  for  a  muscle  or  its  insertion. 
A  single  aponeurosis  may  do  both  of  these.  For  instance,  the  aponeurosis  of 
investment  for  the  glutens  maximus  muscle  continues  downward,  and  the 
muscle  is  aponeurotically  inserted  thereby  into  the  deep  fascia  of  the  thigh. 

ORIGIN  AND  INSERTION  OF  MUSCLES. — These  are  very  arbitrary  terms. 
Usually  the  more  fixed  of  two  points  is  called  the  origin,  the  less  fixed  point,  the 
insertion.  Insertion  may  be  by  tendon  or  by  aponeuroses.  Notice  that  many 
muscles  take  a  large  part  of  their  origin  from  the  deep  fascia  investing  them. 
Attachment  applies  to  both  origin  and  insertion. 

ANATOMICAL  FIBROUS  ARCHES. — You  will,  in  the  course  of  your  reading,  see 
the  above  expression.  The  two  heads  of  muscles  are  always  connected  by  a 
fibrous  arch.  The  following  will  illustrate  the  point :  The  gastrocnemius, 
soleus,  biceps,  flexor  sublimis  digitorum,  pronator  radii  teres,  flexor  longus 
pollicis,  the  biceps  of  the  thigh.  Vessels  and  nerves  are  frequently  described  as 
passing  under  the  fibrous  arch  of  a  muscle. 

THE  SUPERFICIAL  FASCIA — 

1.  Is  found  immediately  under  the  skin  ; 

2.  It  has  two  strata — an  upper  and  a  lower  ; 

3.  The  upper  stratum  contains  fat — the  panniculus  adiposus  ; 

4.  The  lower  stratum  contains  the  cutaneous  vessels  and  nerves  ; 

5.  It  has  no  fat  in  the  eyelids,  penis,  and  scrotum  ; 

6.  It  is  not  attached  to  bony  eminences  ; 

7.  It  has  some  muscles,  called  dermals  ; 

8.  Its  local  special  names  are  cribriform  and  colles  ; 

9.  Its  fat  in  the  palms  and  soles  is  called  granular  fat. 

THE  SEROUS  MEMBRANES. — You  will  be  able  to  demonstrate  on  the  cadaver — 

1 .  They  are  all  related  to  the  lymphatic  system  ; 

2.  They  form  air-tight  cavities,  except  the  female  peritoneum  ; 

3.  They  are  all  thin  and  transparent  ; 

4.  They  completely  or  partially  invest  organs  ; 

5.  Peritoneum,  pleura,  and  pericardium  are  proper  serous  membranes  ; 

6.  The  linings  of  blood-vessels  and  joints  are  subdivisions. 

3 


26  PRACTICAL  ANATOMY, 

SYNOVIAL  MEMBRANES. — In  your  practical  work  on  the  cadaver  you  will  find  : 
(i)  Articular  synovial  membrane  lining  the  capsules  of  movable  joints;  (2) 
vaginal  synovial  membrane  lining  the  ligamenta  vaginales,  surrounding  the 
tendons  to  the  fingers  and  toes,  and  also  in  other  places  where  a  tendon  would 
be  exposed  to  friction  ;  (3)  bursal  synovial  membrane  between  an  eminence  of  bone 
and  a  muscle  playing  thereover.  The  secretion  of  these  synovial  membranes  is, 
by  virtue  of  its  viscidity,  fitted  to  resist  friction.  Synovial  membranes  belong  to 
the  class  of  serous  membranes. 

THE  Mucous  MEMBRANES. — These  communicate  with  the  air.  You  will 
demonstrate  them  lining  the  digestive  tract,  the  genito-urinary  passages,  and  the 
respiratory  tract.  The  margin  between  skin  and  mucous  membrane  is  called  a 
muco-cutaneous  margin.  You  must  demonstrate  this  margin  in  all  regions  of 
the  body.  The  specific  name  of  any  muco-cutaneous  margin  is  determined  by 
the  name  of  the  region,  as  :  (i)  The  nasal ;  (2)  ocular  ;  (3)  oral ;  (4)  anal ;  and  (5) 
vaginal  muco-cutaneous  margin.  These  are  all  anatomical  weak  points,  because 
they  are  junctional  areas. 

NERVE-ENDINGS. — You  should  remember  that  muscles  receive  both  sensory 
and  motor  nerves ;  that  nerve-endings  are  in  tendon,  blood-vessel,  all  the  mem- 
branes, and  skin  ;  that  you  are  not  supposed  to  dissect  out  these  nerve-endings — 
this  belongs  to  histological  and  physiological  research.  You  are  to  note  where 
the  muscle  receives  its  nerve-supply, — usually  on  the  under  surface, — and  then 
trace  the  same  as  far  as  possible. 


THE  HEAD  AND  NECK. 


Any  attempt  to  dissect  the  general  or  special  regions  of  the  head  -and,  neck 
must  be  preceded  by  a  thorough  review  of  those  osteological  parts  associated — (i) 
with  the  attachment  of  muscles  ;  (2)  with  the  limitation  of  surgical  or  physio- 
logical areas  ;  (3)  with  the  transmission  of  vessels  and  nerves  ;  (4)  with  junctional 
areas,  whether  the  union  is  fixed,  as  between  the  teeth  and  alveolus,  or  movable., 


FIG.   7. — THE  SKULL.     (Norma  lateralis. ) 


as  between  the  mandible  and  the  temporal  bone.     To  accomplish  this  interesting 
review  let  the  illustrations  in  the  book,  the  skull,  and  the  cadaver  all  be  used. 

(Fig.  7-) 

I.  The  complete  temporal  ridge  has — (i)  a  frontal  portion  ;  (2)  a  parietal 
portion;  (3)  a  temporal  portion.  From  it  arises  the  temporal  muscle  and  its 
aponeurosis.  The  greater  p^art  of  the  temporal  fossa  is  limited  by  it.  It  begins 

27 ; 


28 


PR  A  CTICAL  ANA  TOMY. 


at  the  external  angular  process  of  the  frontal  bone  and  ends  in  the  posterior  root 
of  the  zygomatic  process  of  the  temporal  bone.  The  two  ends  are  connected 
by  the  zygomatic  arcJi. 


MENTAL 
FORAMEN 
Levator 
menti 
Depressor 
labii  inf. 
THE    CHIN     OR 
MENTAL  PRO- 
TUBERANCE 


Temporal       CORONOID  PROCESS       SIQMOID  NOTCH    External  pterygoid 


CONDYLE 


Platysma 


Depressor  anguli  oris 

EXTERNAL  OBLIQUE  LINE 


GROOVE  FOR  FACIAL  ARTERY 


ANGLE 


FIG.  8. — THE  MANDIBLE.     (Outer  view.) 


External 
pterygoid 


Capsule 


MANDIBULAR 
SPINE 

MANDIBULAR 

FORAMEN 

Spheno-mandi- 

bular  ligament 

Superior 

constrictor 

Mylo-hyoid 

groove 

Internal 
pterygoid 

Stylo- 

mandibular 

ligament 


Temporal 


GROOVE  FOR  SUB- 
LINGUAL  GLAND 
Genio-hyo- 

glOSBUS 

Qeiiio-hyoid 


Digastric 


Mylo-hyoid 

INTERNAL  OBLIQUE  LINE 


GROOVE  FOR  SUBMAXILLARY  GLAND 


FIG.  9. — THE  MANDIIU.K.     (Inner  view.) 

2.  The  zygomatic  arch  has  (i)*a  malar  and  (2)  a  temporal  portion.  It  is 
formed  by  the  zygomatic  process  of  the  malar  and  the  zygomatic  process  of 
the  temporal  bone.  The  arch  has  an  upper  and  a  hwr  border ;  an  outer  and  an 
inner  surface. 


THE  HEAD  AND  NECK. 


29 


3.  The  mandible  has  a  body  and  a  ramus.  On  the  body  find  :  (i)  The 
mental  foramen  ;  (2)  the  external  oblique  line  ;  (3)  the  alveolar  process  ;  (4)  the 
symphysis  menti ;  (5)  the  mental  tubercles  ;  (6)  the  incisive  fossa  ;  (7)  an  internal 
oblique  line  or  mylo-hyoid  ridge  ;  (8)  a  mandibular  spine ;  (9)  a  mandibular 
foramen  ;  (10)  superior  and  inferior  genial  tubercles  ;  (i  i)  a  digastric  fossa  ;  (12) 
a  submaxillary  groove  for  the  submaxillary  gland. 


Zygomaticuo 
major 


Zygomaticus 
minor 


SURFACE  COVERED  BY 
oocipito-frontalis 


Corrugator 
superoilii 


Tendo  oculi 
Crbicularia 

palpebrarum 
Levator  labii  supe- 

rioris  alaeque  nasi 


Levator  labii 
auperioria 


Levator  anguli  oris 

Compressor  naris 

Depressor  alee  nasi 
Orbicularis  oris 


FIG.   10. — THE  SKULL.     (Norma  facialis.) 


The  ramus  has  (i)  a  coronoid  process  ;  (2)  a  sigmoid  notch  ;  (3)  a  condylar 
process.  The  condylar  process  consists  of  a  condyle  and  a  neck. 

ON  THE  FACE  LOCATE  (Fig.  10)  :  (i)  The  anterior  nares  ;  (2)  the  nasal  bones  ; 
(3)  the  temporal,  frontal,  orbital,  and  maxillary  processes  of  the  malar  bone  ;  (4) 
the  supraorbital  and  infraorbital  arches  ;  (5)  the  internal  and  external  angular 
processes  of  the  frontal  bone  ;  (6)  the  floor  of  the  orbit,  and  in  it  the  infraorbital 
canal,  containing  an  artery,  nerve,  and  vein  of  the  same  name  ;  (7)  the  infra- 
orbital  foramen,  the  terminus  of  the  infraorbital  canal ;  (8)  the  supraorbital 


3° 


PRACTICAL  ANATOMY. 


Maseeter 


Tensor  palati 
Azygos  uvulae 

Superior  constrictor 
Internal  pterygoid 

Tensor  palati 

Tensor  tympanl 

Levator  palati 

Rectus  capitis  anticus  major 

Rectus  capitis  anticus  minor 

Anterior  common  ligament  of  spine 
Vertical  part  of  crucial  ligament 

Check  ligament 
Capsular  ligament 


Posterior  oeeipito-atlantal  ligament 
Superior  oblique 

Rectus  capitis  posticus  major 
Rectus  capitis  postious  minor 


Iiigamentum  nuchse 
_   Trapezius 


1  i<;.    ii.  -Tin    SK.UI.L.     (Nonna  hasilaris.) 


THE   HEAD   AND   NECK.  31 

foramen  in  the  frontal  bone  ;  (9)  the  intermaxillary  suture  ;  (10)  the  naso-frontal 
suture  ;  (i  i)  the  superciliary  ridge  ;  (12)  the  interfrontal  or  metopic  suture  or  its 
remains. 

ON  THE  BASE  OF  THE  SKULL  (Fig.  1 1)  LOCATE:  (i)  The  foramen  magnum  ;  (2) 
the  occipital  condyles  ;  (3)  the  digastric  groove  for  the  posterior  belly  of  the  digas- 
tric muscle  ;  (4)  the  jugular  process  for  the  rectus  capitis  lateralis  ;  (5)  the  styloid 
process  of  the  temporal  bone  ;  (6)  the  glenoid  fossa  with  the  Glaserian  fissure 
dividing  the  articular  from  the  non-articular  part  of  the  same  ;  (7)  the  internal  and 
external  pterygoid  plates  of  the  pterygoid  process  of  the  sphenoid  bone  ;  (8)  the 
pterygoid  fossa  for  the  internal  pterygoid  muscle  ;  (9)  the  jugular  foramen  for 
the  ninth,  tenth,  eleventh  nerves  and  jugular  vein  ;  (10)  the  carotid  canal  in  the 
petrosa  for  the  internal  carotid  artery  and  sympathetic  nerve  ;  (i  i)  the  foramen 
spinosum  for  the  great  meningeal  artery  ;  (12)  the  posterior  nares  1(13)  the  hard 
palate  ;  (14)  the  hamular  process,  around  which  plays  the  circumflexus  palati. 

LOCATE  THE  ATTACHMENT  OF  THESE  MUSCLES  (Figs.  7-10):  (i)  Temporal  ; 
(2)  masseter ;  (3)  pterygoid,  internal  and  external  ;  (4)  buccinator  ;  (5)  platysma  ; 
(6)  digastric  ;  (7)  orbicularis  oris  ;  (8)  depressor  labii  inferioris  ;  (9)  levator  menti  ; 
(10)  levator  labii  superioris  ;  (i  i)  levator  anguli  oris  ;  (12)  corrugator  supercilii  ; 
(13)  zygomaticus,  major  and  minor  ;  (14)  compressor  naris  ;  (15)  depressor  alae 
nasi ;  (i 6)  levator  labii  superioris  alaeque  nasi ;  (17)  the  rectus  capitis  anticus, 
major  and  minor;  (18)  the  tensor  palati;  (19)  the  azygos  uvulae;  (20)  levator 
palati  ;  (21)  tensor  tympani ;  (22)  depressor  anguli  oris. 

LOCATE  THE  FOLLOWING  FISSURES  :  (i)  The  fronto-parietal  ;  (2)  the  temporo- 
parietal  ;  (3)  the  interparietal  or  sagittal ;  (4)  the  occipito-parietal ;  (5)  the 
interfrontal ;  (6)  the  fronto-nasal ;  (7)  the  fronto-maxillary  ;  (8)  the  malo-frontal  ; 
(9)  the  malo-zygomatic ;  (10)  the  malo-maxillary  ;  (11)  the  naso-maxillary  ; 
(12)  the  intermaxillary  ;  (13)  the  symphysis  menti ;  (14)  the  spheno-maxillary  ; 
(15)  the  petro-occipital ;  (16)  the  palato-maxillary ;  (17)  temporo-mandibular 
and  occipito-atloid  articulations  are  the  only  movable  joints  in  this  region. 

INCISIONS  FOR  LOCATING  THE  FOLLOWING  STRUCTURES  : 

1.  The  supraorbital  nerve,  artery,  and  vein  (fifth  nerve  and  seventh  nerve). 

2.  The  infraorbital  nerve,  artery,  and  vein  (fifth  nerve  and  seventh  nerve). 

3.  The  mental  nerve,  artery,  and  vein  (fifth  nerve  and  seventh  nerve). 

4.  The  facial  artery  and  vein  and  their  branches. 

5.  The  facial  nerve  and  its  facial  branches  and  communications. 

6.  The  duct  of  Stenson  and  transverse  facial  artery. 

The  Mental  Nerve. — Turn  the  skin  aside  from  the  intersectional  point  indi- 
cated in  figure  1 2.  With  the  forceps  dissect  out  the  leash  of  mental  nerves,  anp 
find  them  continuous  with  branches  of  the  facial  nerve,  or  seventh  cranial.  (Fig. 
1 6.)  Find  also  the  mental  branch  of  the  inferior  dental  artery  coming  through 
the  same  foramen — the  mental. 

The  Supraorbital  Nerve. — Turn  the  skin  back,  beginning  at  the  intersectional 
point  in  the  figure.  Find  with  the  forceps  the  leash  of  the  supraorbital  nerve 
(Fig.  1 6)  anastomosing  with  the  supraorbital  part  of  the  facial  portion  of  the 
seventh  nerve. 

The  Infraorbital  Nerve. — Turn  the  skin  back,  beginning  at  the  intersectional 
point  in  the  figure.  Here,  with  the  forceps,  you  will  find  a  large  leash  of  nerves, 
the  terminus  of  the  infraorbital  nerve.  You  will  see  that  its  branches  are  con- 
tinuous with  the  infraorbital  portion  of  the  seventh  cranial  nerve.  Find  also  the 
branches  of  the  infraorbital  artery  accompanying  the  nerve. 

Stenson' S  duct  is  the  excretory  duct  for  the  parotid  gland.  Turn  the  skin 
back  from  the  intersectional  point  indicated.  Above  the  duct  you  will  find  the 
transverse  facial  artery,  a  small  branch  of  the  temporal.  Below  the  duct  you 
will  find  branches  of  the  facial  nerve. 


32  PRACTICAL    ANATOMY. 

The  levator  labii  superioris  covers  the  infraorbital  nerve  and  artery.  This 
muscle  arises  from  the  margin  of  bone  below  the  orbit.  (Fig.  10.)  It  is  inserted 
into  the  orbicularis  oris. 

The  levator  anguli  oris  arises  from  the  canine  fossa  below  the  infraorbital 
foramen.  It  is  inserted  into  the  angle  of  the  mouth.  It  may  be  seen  by  pulling 
the  leash  of  nerves  to  one  side.  The  leash  of  nerves  lies  between  the  above  two 
muscles.  (Fig.  10.) 

The  Depressor  Labii  Inferioris. — Remove  the  skin  a  little  further  in  the 
region  of  the  mental  nerves,  and  find  the  depressor  of  the  lower  lip.  This 
muscle  is  quadrangular  in  form.  Fully  one-half  of  its  outer  surface  lies  under 


\ 


\ 


FIG.  12. — PRIMARY  INCISIONS  IN  DISSKCTION  01   THE  KACK. 


the  depressor  anguli  oris  (Fig.  13).  The  muscle  arises  from  the  upper  part  of  the 
external  oblique  line  of  the  mandible,  and  is  inserted  into  the  lower  lip. 

The  depressor  anguli  oris  (Fig.  13)  will  be  found  arising  from  the  lower  part 
of  the  external  oblique  line  of  the  mandible.  It  is  triangular  in  form.  It  over- 
laps the  outer  one-half  of  the  depressor  labii  inferioris.  Now  cut  the  origin  of 
this  muscle,  and  pull  the  same  aside  and  expose  the  whole  of  the  muscle  that 
it  overlaps.  (Fig.  17.) 

CAUTION. — In  all  dissections  about  the  face  care  must  be  taken  to  cut  close 
to  the  skin.  The  branches  of  the  seventh  nerve  lie  beneath  the  muscles  and 
can  not  be  injured  if  you  take  the  precaution  just  given. 


THE  HEAD   AND   NECK. 


33 


The  Orbicularis  Oris. — Remove  the  skin  around  the  mouth  and  expose  this 
muscle.  (Fig.  14.)  This  muscle  has  a  rather  strong'fascial  attachment  to  the 
alveolus  of  the  superior  maxilla.  ^ 

The  zygomatici  major  and  minor  (Fig.  14)  arise  from  the  malar  bone,  and 
are  inserted  into  the  outer  part  of  the  upper  lip. 

The  levator  labii  superioris  alaeque  nasi  is  inserted  into  the  wing  of  the 
nose  and  the  upper  lip.  It  arises  from  the  nasal  process  of  the  superior  maxilla, 
on  the  margin  of  the  orbit. 


Corrugatpr 
supercilii 


Pyramidalis 

Levator  labii 

superioris 

alaeque  naai 

Levator  labii 

superioris 

Compressor 

narium 
Levator  anguli 

oris 

Naso-labialis 
Depressor  alae 

nasi 
Orbicularis  oris 

Buccinator 

Depressor 

anguli  oris 

Depressor  labii 

inferioris 
Levator  inenti 
Mylo-hyoid 

Anterior  belly  of 
digastric 


Temporal 


Zygomaticua 
major 


Posterior  belly 
of  digastric 

Splenius  capitis 

Stylo-hyoid 

Sterno-maatoid 


Levator  anguli 
scapulae 


Scalenus 
medius 


Scalenus  anticus 


FIG    13  — THE  DEEPER  LAYER  OK  THE  MUSCLES  OF  THE  FACE  AND  NECK. 


The  Orbicularis  palpebrarum  surrounds  the  base  of  the  orbit.  It  consists 
of  two  sets  of  fibres.  One,  called  the  palpebral,  covers  the  palpebra>  or  lids  ;  the 
other  is  external  to  this,  and  blends  above  with  the  occipto-frontalis  muscle.  It 
has,  internally,  a  firm,  triple  attachment  to  the  internal  angular  process  of  the 
frontal  bone,  and  to  the  nasal  process  of  the  superior  maxilla.  Between  these 
two  you  will  find  a  short,  stout  tendon  that  can  be  mistaken  for  nothing  else — 
the  tendo  oculi  or  tendo  palpebrarum.  Figure  10  shows  its  origin  from  the  nasal 
process  of  the  superior  maxilla  in  front  of  the  lachrymal  groove.  Trace  the 
tendon  toward  the  upper  and  lower  lids  and  observe  how  it  divides. 


34 


PRACTICAL    ANATOMY. 


The  Levator  Menti,  or  Levator  Labii  Inferioris  (Fig.  13). — This  is  the 
muscle  by  which  the  low"er  lip  is  protruded  and  elevated  at  the  same  time.  Cut 
th/ough  the  mucous  membrane  and  you  will  come  to  the  muscular  fibres.  This 
muscle  arises  from  the  incisive  fossa,  and  is  inserted  into  the  integument  of  the 
chin,  on  a  plane  lower  than  the  origin  of  the  muscle. 

The  compressor  narium  (Fig.  14),  a  small  muscle,  arises  from  the  superior 
maxilla.  (Fig.  10.)  It  is  inserted,  by  an  aponeurosis  across  the  bridge  of  the 
nose,  into  its  fellow  of  the  opposite  side.  This  is  a  small  muscle  at  best,  and 
very  hard  to  demonstrate  on  prepared  material. 


Epicranial 
aponeuroais 


Orbicularis  palpebrarun 


Fyramidalis 

Levator  labii  superior-is 

alscque  na3i 
Compressor  narium 

Dilatator  naris  anterior 
Dilatator  uaris  posterior 

Levator  labii  superioris 
Zygomaticus  minor 

Levator  anguli  or  is 
Orbicularis  oris 


Depressor  labii  inferioris 
Depressor  anguli  oris 


FIG.  14. — THE  SUPERFICIAL  MUSCLES  OK  THE  HEAD  AND  NECK. 

The  corrugator  supercilii  (Fig.  13)  is  seen  by  cutting  in  the  mid-line 
above  the  nose  through  the  skin  and  fasciae.  It  arises  from  the  superciliary 
ridge  (Fig.  10),  and  is  inserted  into  the  under  part  of  the  orbicularis  palpebrarum. 
In  action  it  produces  the  deep  vertical  furrows  of  the  forehead. 

The  pyramidalis  nasi  (Fig.  14)  is  a  part  of  the  occipito-frontalis,  continued 
on  to  the  nose,  and  inserted  into  the  compressor  narium. 

The  dilator  naris  anterior  arises  from  the  lateral  cartilage  of  the  nose,  and 
is  inserted  into  the  skin  near  the  margin  of  the  nose,  well  in  front. 


THE   HEAD   AND   NECK. 


35 


The  dilator  naris  posterior  arises  from  the  superior  maxillary  bone,  from 
the  nasal  notch,  and  is  inserted  into  the  skin  of  the  margin  of  the  nostril,  well 
back.  These  two  dilator  muscles  antagonize  the  compressor  nariinu.  Remove 
the  skin  from  the  forehead,  and  expose  the  anterior  belly  of  the  occipito-frontalis. 
We  are  at  present  concerned  only  with  the  insertion  of  this  muscle.  Its  anterior 
fibres  are  continued  on  to  the  nose  as  the  pyramidalis  nasi ;  its  middle  and  outer 
blend  with  the  outer  portion  of  the  orbicularis  palpebrarum. 

The  muscles  of  facial  expression,  those  which  you  have  just  dissected, 
are  called  dermal  muscles,  on  account  of  their  insertion,  being  of  such  a  nature 
as  to  move  the  skin,  in  a  most  unique  manner.  These  muscles  are  innervated  by 
the  facial  or  seventh  cranial  nerve.  (Fig.  16.)  They  are  in  the  superficial  fascia — 
in  fact,  they  occupy  the  fascia  to  such  a  degree  that  some  good  authors  speak  of 
the  absence  of  facial  superficial  fascia.  By  their  action  they  confer  on  the  human 
face  facial  expression  in  its  broadest  sense. 

Is  not  the  facial  nerve  more  than  an  ordinary  motor  nerve  ?     In  other  words, 


FIG.   15. — SCHEME  OF  FACIAL  NERVE  COMMUNICATING  WITH  THE  FIFTH  CRANIAL  NERVE. 


is  not  this  nerve  eligible  to  promotion  from  the  rank  and  file  of  ordinary  motor 
nerves  to  a  place  among  those  nerves  which  are  designated  special  sense  nerves  ? 
For  the  sake  of  arousing  your  interest  in  the  difficult  dissection  of  this  nerve, 
you  will  pardon  a  digression  for  the  purpose  of  answering  the  above  questions. 

A  slight  blow  on  the  ligamentum  patellae  produces  reflex  extension  of  the 
leg  on  the  thigh.  The  steps  were  (i)  conduction  of  pain,  by  a  sensory  nerve,  to 
a  cortical  motor  area,  and  (2)  an  almost  simultaneous  contraction  of  the  extensor 
quadriceps  femoris  ;  (3)  a  record  of  the  blow  was  recorded  as  memory.  A  com- 
plete moto-sensory  cycle  was  the  result.  The  nerve  that  conveyed  the  sensation 
of  pain  to  the  brain  is  called  a  nerve  of  common  sensation  ;  the  one  that  produced 
motion  in  the  extensor  muscles  is  called  a  motor  nerve. 

The  retina  responds  to  light,  the  auditory  nerve  to  sound,  the  olfactory,  to 
odors.  Each  nerve  records  its  experience  in  the  brain.  Now,  see  what  the 
facial  nerve  does  !  It  produces  motion  of  a  reflex  character,  as  do  ordinary 
motor  nerves.  It  is  the  only  nerve  by  which  vision,  audition,  olfaction,  and 


36  PRACTICAL   ANATOMY. 

gustation  manifest  themselves  in  the  primitive  state.  The  sight  of  cruelty,  the 
sound  of  martial  music,  the  odor  of  Limburger  cheese,  the  taste  of  some  extra- 
ordinary viand,  are  facially  expressed,  and  read  off  by  the  world  as  disapproval, 
patriotic  enthusiasm,  repulsion,  satisfaction.  If,  then,  auditory,  optic,  and 
gustatory  nerves  are  capable  of  conveying  an  impression  to  the  brain  for  record, 
are  they  entitled  to  the  designation  "  special  sense  "  any  more  than  is  the  facial, 
which  does  its  own  work,  and  facially  expresses  to  the  world  the  recorded 
experiences  of  all  the  so-called  nerves  of  special  sense  ?  Is  not  this  nerve  a 
special  sense  nerve  of  facial  pantomime  ? 


SUPRA-ORBITAL 

PALPEBRAL  TWIG 

OF"  LACHRYMAL 

INFRA TROCHLEAR 

TEMPORAL 

BRANCH  OF 

SEVENTH 

MALAR  BR. 
OF  SEVENTH 
MAXILLARY 
1)1  V.  OF  FIFTH 
INFRA- 
ORBITAL 
BR.  OF  SEVENTH 


BUCCAL  BRANCH 
OF  SEVENTH 


MENTAL  BRANCH 
OF  MANDIBULAR 


S  UPRA  -MA  NDIB  ULA  R 
BRASCH  OF  SEVENTH 


INFRA  -MA  NDIB  t  Y,  .1  K 
BRANCH  Of  SEVENTH 


POSTERIOR 

AURIC  I  "I. Ml 

A  URICULO- 
TEUPORAL 

GREAT 
OCCIPITAL 

FACIAL 


LESSER  OCCIPITAL 
GREAT  A  URICULAR 


SUPERFICIAL 

CERVICAL 


FIG.   16.— SUPERFICIAL  DISTRIBUTION  OF  THE  FACIAL  AND  OTHKK  NKRVKS  OF  TIIK  HKAD. 

(After  Hirschfeld  and  Leveille.) 


The  Facial  Nerve  (Fig.  16):  Its  Dissection  on  the  Face. — Remove  the 
skin.  Cut  down  through  the  parotid  gland  in  the  direction  of  the  vertical  line  in 
figure  1 2.  It  is  necessary  to  go  through  about  one-half  of  an  inch  of  gland  sub- 
stance. Take  the  forceps,  and  find  a  nerve  trunk  about  the  size  of  a  knitting- 
needle.  This  will  be  the  inferior  division  of  the  nerve — the  cennco-facial  part. 
Follow  this  branch  up  a  little  further,  and,  very  deeply  located,  you  will  find  the 
main  tnin/c  of  the  nerve.  From  this  you  can  trace  out  all  the  facial  branches, 
in  this  manner  :  Put  a  small  piece  of  tape  around  the  main  trunk.  Pull  on  this, 


THE   HEAD   AND   NECK.  37 

and  at  the  same  time  cut  the  skin,  fascia,  and  gland  substance,  in  the  direction 
of  the  branches,  with  scissors.  You  will  find  dissection  of  this  nerve  somewhat 
difficult  the  first  time  you  make  the  trial.  Any  amount  of  advice,  added  to 
what  has  previously  been  said,  will  not  help  you.  Just  be  careful,  and  expose 
one  branch  at  a  time. 

Communications  of  the  Facial  Nerve  on  the  Face  with  other  Nerves 

(Fig.  15): 

1.  The  seventh  nerve  -f-  mental  branch  of  the  fifth  nerve  at  mental  foramen. 

2.  The  seventh  nerve  +  infraorbital  branch  of  thev  fifth  nerve  at  infraorbital 
foramen. 

3.  The  seventh  nerve  +  supraorbital  branch  of  the  fifth  nerve  at  supraorbital 
foramen. 

4.  The  seventh  nerve  -f-  auriculo-temporal  branch  of  fifth  on  temporal  muscle. 

5.  The  seventh  nerve  +  malar  branch  of  temporo-malar  of  fifth  nerve  on 
malar  bone. 

6.  The  seventh  nerve  +  temporal  branch  of  temporo-malar  of  fifth  nerve 
above  zygoma. 

7.  The  seventh  nerve  -f-  great  auricular  nerve  of  cervical  plexus  behind  the 
ear. 

8.  The  seventh  nerve  -j-  small  occipital  nerve  of  cervical  plexus  behind  the 
ear. 

9.  The  seventh  nerve  -f-  lachrymal  and  infratrochlear  branches  of  the  fifth 
nerve. 

10.  The  seventh  nerve  -J-  great  occipital.  Posterior  division  of  second  cer- 
vical nerve. 

It  will  appear  from  the  foregoing  that  the  nerve-supply  of  the  face  is  a  very 
complicated  proposition.  Such,  however,  is  not  the  case,  since  the  whole  nerve- 
distribution  can  be  reduced  to  : 

1.  Motor  nerves  to  the  muscles  of  expression  =  seventh  nerve. 

2.  Sensory  nerves  to  the  skin  over  the  muscles  =  fifth  nerve. 

3.  Sympathetic  nerves — the  nervi  molles — on  facial  artery. 

4.  Communicating  branches  to  adjacent  areas. 

Divisions  and  Facial  Branches  of  the  Facial  Nerve. — The  nerve  divides 
into  two  branches  :  (i)  An  upper  division  that  supplies  the  upper  half  of  the 
face  and  the  temporal  region  ;  (2)  a  lower  division  that  supplies  the  lower 
half  of  the  face  and  the  neck.  (Fig.  16.) 

The  temporo-facial  division  gives  off : 

1.  Temporal  branches  to  the  temple  and  forehead. 

2.  Infraorbital  branches  below  the  orbit. 

3.  Malar  branches  to  the  zygomatic  muscles. 
The  cervico-facial  division  gives  off : 

1.  A  buccal  branch  to  the  buccinator  muscle. 

2.  A  supramandibular  branch  above  the  jaw. 

3.  An  inframandibular  branch  below  the  jaw. 

The  name  pes  anscrinus  is  applied  to  the  divergence  of  these  six  nerves  from 
the  two  primary  divisions  of  the  seventh  nerve. 

The  auriculo-temporal  nerve  will  be  found  in  front  of  the  ear  just  behind 
the  temporal  artery.  It  is  a  sensory  branch  of  the  fifth,  and  supplies  the  side  of 
the  scalp  and  the  external  in  front  with  sensation. 

Find  these  arteries  on  the  face  (Fig.  1 7)  : 

1.  The  frontal  in  the  inner  angle  of  the  orbit. 

2.  The  nasal  above  the  tendo  oculi. 

3.  The  lachrymal  in  the  outer  angle  to  the  upper  lid. 

4.  The  transverse  facial  on  the  malar  bone. 


38  PRACTICAL   ANATOMY. 

5.  The  supraorbital,  with  the  supraorbital  nerve. 

6.  The  infraorbital,  with  the  infraorbital  nerve. 

7.  The  mental,  with  the  mental  nerve. 

8.  The    facial    artery   (Fig.    17)    crosses    the    mandible    in  front  oi    the 
masseter  muscle.      It  is   surrounded  by  some  very  delicate  sympathetic  nerves, 


Orbicularia  palpebrarum 
muscle 


Transverse  facial  artery 
Zygomatious  minor 
muscle 

Zygomatious  major 
muscle 


Buccinator  muscle 
Masseterie  branch 
Masseter  muscle 


Stylo-pharyngeus 

muscle 

Stylo-glossus  muscle 
Ascending  palatine 

branch 
Tonsillar  branch 


Facial  artery 
External  carotid 
artery 

Posterior  belly  of 
digastric  muscle 

Lingual  artery 


Frontal  branch  of  ophthalmic 

artery 

Nasal  branch  of  ophthalmic 
artery 


Angular  artery 
Levator  labii  super- 
ior is   et   alas    nasi 
muscle 

Infraorbital  artery 
Le'vator  labii  super- 
ioris  proprius 
Lateralis  nasi  ar. 
Levator  anguli  oris 
muscle 

Artery  of  septum 

Superior  coronary 

artery 

Risorius  muscle 

Inferior  coronary  artery 

Mental  branch  of  inferior 

dental  artery 
Depressor  labii  inferioris 

muscle 

Inferior  labial  arlrrti 

Depressor  anguli  oris 

muscle 

Submental  artery 
Branches  to  sitbmaxillary 
gland 

Anterior  belly  of  digastric  muscle 
Mylo-hyoid  muscle 


Hyo-glossus  muscle 


HYl'OtiLOSSAL  NERVE 


Kic.   17.— SCIIKMK  OK  TIIK  FACIAL  ARTKRY. 


which  can  be  demonstrated,  if  you  remove  all  the  fat,  with  ether,  and  permit  the 
ether  to  evaporate.      These  nerves  are  the  ncri'i  uiolles.    They  regulate  blushing. 
H miidics  of  the  /'*iifid/  Artery  on  the  Face  : 

1.  The  inferior  coronary,  between  mucous  membrane  and  orbicularis  oris. 

2.  The  superior  coronary,  between  mucous  membrane  and    orbicularis    oris. 

3.  The  inferior  labial,  under  the  muscles  of  the  chin. 


THE   HEAD   AND   NECK. 


39 


4.  The  lateralis  nasi,  to  the  side  of  the  nose. 

5.  The  angular,  to  the  inner  angle  of  the  orbit. 

6.  Muscular  branches  to  the  various  muscles. 

Anastomosis  takes  place  between  the  facial  and  all  the  arteries  on  the  face 
above  enumerated. 

The  veins  of  the  face  (Fig.  18)  accompany  the  arteries,  and  take  the  same 
names,  as  a  rule.  (Fig.  17.)  They  must  be  dissected  with  the  arteries  and 


Frontal 


Stipraorbital  vein 
Communication  with 

ophthalmic  vein 
Transverse  nasal  vei> 


Angular  vein 
Lateral  nasal  veins 

Transverse  facia 

vein 
Superior  labial  or 

coronary  vein 

Anterior  pterygoid 

or  deep  facial  vein 

Inferior  coronary 

vein 

Facial  vein 

Inferior  labial  vein 

Submental  vein 
Lingual  vein 

Superior  thyroid 
vein 

Middle  thyroid 
vein 

Sterno-mastoid 

Anterior  jugular 

vein 

Communication 
between  anterior 
jugular  veins 

Platysma 


Anterior  temporal  vein 
Posterior  temporal  rein 

Deep  temporal  vein 
Parotid  lymphatic  glands 
Common  temporal  vein 
Internal  maxillary  vein 
Occipital  vein 
Temporo-maiillary  vein 
Posterior  auricular  vein 

Occipital  lymphatic  glands 
Sterno-masloid  lymphatic 

glands 

Communication  between 
facial    and    external 
jugular  veins 
Svbmaxillary  lymphatic 

glands 

Internal  jugular  vein 
Posterior  external  jugular 

vein 
External  jugular  vein 


Superficial  cervical  chain 
of  glands 


-   Transverse 

cervical  vein 

^-  Suprascapular 
vein 


Jugido-cephalic 
vein 


m  • 

FIG.   18. — THE  SUPERFICIAL  VEINS  AND  LYMPHATICS  OF  THE  SCALP,  FACE,  AND  NECK. 


nerves.      These  veins  must  be  handled  very  carefully,  not  to  be  injured,  as  they 
are  very  easily  ruptured. 

Observe  the  deep  temporal  vein  piercing  the  temporal  fascia,  above  the 
zygoma.  This  returns  blood  from  the  temporal  muscle.  Observe  the  confluence 
of  the  internal  maxillary  vein,  in  front  of  the  ear,  in  the  substance  of  the  parotid 
gland,  with  the  temporal  vein,  and  the  result  of  their  confluence — the  temporo- 
inaxillary  vein.  Observe  the  communication  between  the  facial  vein  and  the 
external  jugular;  also  the  communication  between  the  angular,  supraorbital, 
and  ophthalmic  veins.  Erysipelas  of  the  face  may  reach  the  meninges  through 
this  communication.  The  ophthalmic  vein  opens  into  the  cavernous  sinus. 


40  PRACTICAL   ANATOMY. 

The  parotid  gland  (Fig.  20)  is  located  by  limitation  : 

1.  Superiorly,  limited  by  the  zygomatic  arch. 

2.  Inferiorly,  limited  by  the  angle  of  the  mandible. 

3.  Anteriorly,  limited  by  the  mid-line  of  the  masseter. 

4.  Posteriorly,  limited  by  the  mastoid  process  and  sterno-mastoid. 

5.  It  sends  in  prolongations  as  follows  (Fig.  19)  : 

The  inner  surface  is  irregular,  sending  (i)  a  large  process  of  gland  tissue,  in 
front  of  the  styloid  process  of  the  temporal  bone,  the  same  also  occupying  the 
non-articular  part  of  the  glenoid  cavity  ;  (2)  a  large  process  behind  the  styloid 
and  under  the  mastoid  process  and  sterno-cleido-mastoid  muscle. 

Parotid  fascia  is  the  name  given  to  the  deep  fascia  covering  the  outer  sur- 


PALATINE  PROCESS  OF  SUPERIOR 
MAXILLA 


ZYGOMATIC  ARCH 


HORIZONTAL  PLATE  OF  PALATE  BONE 


GLENOID  FOSSA 


r«rnlid  Gland 


STVLOID  PROCESS 
Parotid  Gland 


MASTOID  PROCESS 


FIG.  19. — SHOWING  SCHEMATICALLY  THE  DEEP  PART  OK  THE  PAROTID  GLAND  EMBRACING 

THE  STYLOID  PROCKSS. 

face  of  this  gland.     You   have  already  cut  through   the  gland  vertically  to  find 
the  seventh  nerve. 

Contents  of  the  Parotid  Gland  : 

1.  The  facial  nerve  and  pes  anserinus. 

2.  The  auricula-temporal  branch  of  the  fifth  nerve. 

3.  The  external  carotid  artery  and  its  three  terminals. 

4.  The  posterior  auricular,  temporal,  and  transverse  facial  arteries. 

5.  The  internal  maxillary  artery  and  vein. 

6.  The  temporo-inaxillary  vein. 

7.  A  branch  of  the  great  auricular  nerve  to  the  seventh. 

Excretory  Duct  of  the  Parotid  (Fig.  20). — Stenson's  duct  crosses  the 
masseter  muscle  on  a  line  from  the  centre  of  the  upper  lip  to  the  lobule  of  the 
ear.  It  perforates  the  buccinator  muscle,  and  opens  into  the  vestibule  of  the 
oral  cavity,  opposite  the  second  upper  molar  tooth. 


THE  HEAD  AND  NECK.  41 

1 .  Hozv  may  the  dermal  muscles  be  grouped  ? 

They  may  be  grouped  about  the  four  apertures  :  the  orbit,  the  ear,  the  nose, 
and  the  mouth.  Their  action  seems  to  be  secondary  to  the  special  senses  of 
hearing,  smell,  sight,  and  taste,  since  they  open  and  close  these  openings  to  a 
variable  extent. 

2 .  Give  the  bony  attachments  of  the  orbiculans  oris. 

This  muscle  is  attached  to  the  upper  and  also  to  the  lower  incisive  fossa,  and 
to  the  alveolar  processes. 

3.  Has  the  orbiculans  oris  any  antagonists?    If  so,  name  them. 

Yes  ;  superiorly,  levator  labii  superioris,  levator  anguli  oris,  zygomaticus 
minor,  zygomaticus  major  ;  inferiorly,  depressor  labii  inferioris,  depressor  anguli 
oris,  levator  menti,  risorius. 


SOCIA  PAROTIDIS 


SUBLINGUAL  GLAND 


DUCT  OF  SUBMAXILLARY 

GLAND 
Mylo-hyoid  muscle 


Anterior  belly  of 
digastric  muscle 


DEEP  PORTION  OF  SUBMAXILLARY  GLAND 

FIG.  20. — THE  SALIVARY  GLANDS. 


PAROTID  GLAND 


Massetcr  muscle 


Ster  no  -m  astoid 
muscle 


Posterior  belly  of 
digastric  muscle 


SUBMAXILLARY  GLAND. 
DRAWN  BACKWARDS 


Loop  of  fascia 


4.  Name  the  foramen  between  the  origins  of  the  levator  labii  superioris  and  the 
levator  anguli  oris. 

The  infraorbital,  transmitting  the  infraorbital  vessels  and  nerves. 

5.  Locate  on  a  patient  the  foramen  mental ct  and  tell  what  it  transmits. 

This  foramen  is  located  at  the  junction  of  the  mento-Meckelian  and  dentary 
parts  of  the  mandible,  one-half  of  an  inch  below  the  gingiva  of  the  second  bicuspid 
tooth  ;  it  transmits  the  mental  branches  of  the  inferior  dental  vessels  and  nerves. 

6.  What  is  the  function  of  the  mental  nerves  and  with  what  do  they  communi- 
cate ? 

The  function  is  to  supply  the  skin  of  the  lower  lip  and  chin  ;  they  communi- 
cate with  mental  branches  of  the  facial  nerve. 

7.  Name  the  aural  group  of  dermal  muscles,  and  give  their  function. 
Attrahens  aurem,  attolens  aurem,  retrahens  aurem.      These  muscles  are  mere 

vestiges  in  man,  often   incapable   of  demonstration.     They  are  best  studied    on 
domestic  animals,  as  the  dog  and  rabbit.     Their  function  is,  first,  to  enlarge   the 
4 


42  PRACTICAL  ANATOMY. 

auditory  canal  by  rendering  tense  the  cartilaginous  parts  ;  and,  second,  to  direct 
the  external  ear  toward  a  given  noise.  These  muscles  are  supplied  by  the 
seventh  cranial  nerve. 

8.  Describe  the  rationale  of  a  complete  frown. 

A  proper  frown  consists  of  vertical  and  horizontal  corrugations.  The  verti- 
cals are  produced  by  the  action  of  the  corrugator  supercilii  on  the  anterior  belly 
of  the  occipito-frontalis  muscle,  acting  on  this  so  as  to  deflect  inward  its  muscular 
belly  and  the  skin  covering  the  same.  The  horizontal  ridges  are  the  result  of 
the  same  force,  intensified  to  some  extent  by  gravity. 

9.  Locate  the  infraorbital  plexus  and  give  its  formation. 

It  is  located  one-half  of  an  inch  external  to  the  wing  of  the  nose.     It  lies 


Submaxillary 


Superior  carotid 


Occipital 


Inferior  carotid 


Fir,.  21. — CERVICAL  TRIANGI.KS. 

under  cover  of  the  levator  labii  superioris,  and  is  formed  by  a.  communication 
between  the  infraorbital  branch  of  the  fifth  and  the  infraorbital  branches  of  the 
seventh  nerve. 

10.  Name  and  locate  the  great  anastomotic  blood  areas  on  the  face  and  tell  limv 
they  are  formed, 

The  facial  branch  of  the  external  carotid,  the  ophthalmic  branch  of  the 
internal  carotid  artery,  the  internal  maxillary  branch  of  the  external  carotid,  and 
the  temporal  branches  of  the  external  carotid  are  the  branches  of  arterial  trunks 
concerned  in  the  rich  blood-supply  to  the  face. 

Anastomotic  areas:  (Fig.  17)  (i)  The  ophthalmic  anastomoses  with  the  tem- 
poral, forming  the  supraorbital  anastomosis,  and  with  the  angular  branch  of 
the  facial  artery  at  the  iniu-r  base  of  the  orbit,  forming  the  angular  anastomosis. 
( 2)  The  transverse  facial  artery  anastomoses  with  the  masseteric  branch  of  the 


THE  HEAD  AND  NECK.  43 

facial  artery  on  the  outer  surface  of  the  masseter  muscle,  forming  the  masseteric 
anastomosis.  (3)  The  infraorbital  anastomoses  with  the  facial,  below  the  orbit, 
to  form  the  infraorbital  anastomosis.  (4)  The  mental  branch  of  the  inferior 
dental  artery  anastomoses  with  the  inferior  labial  branch  of  the  facial  artery, 
forming  the  mental  anastomosis.  (5)  In  the  facial  mid-line  the  corresponding 
arteries  of  opposite  sides  of  the  face  anastomose.  At  the  aural,  ocular,  nasal, 
and  oral  muco-cutaneous  junctions  capillary  anastomosis  takes  place.  (6)  The 
arterial  anastomoses  above  referred  to  are  attended  by  venous  anastomoses. 
The  mental,  infraorbital,  and  supraorbital  may  be  compressed  at  their  respective 
exit  foramina.  The  facial  may  be  compressed  on  the  mandible  just  in  front  of  the 
masseter  muscle.  (7)  The  important  communication  on  the  face  is  between  the 
ophthalmic  and  angular,  by  which  route  facial  erysipelas  may  reach  the  meninges, 
since  the  ophthalmic  vein  opens  into  the  cavernous  sinus  of  the  dura  mater. 

1 1 .  Explain  briefly  the  parotid  gland. 

The  gland  is  located  in  a  depression  having  the  following  limitations  :  above, 
the  zygomatic  arch  ;  below,  the  angle  of  the  mandible  and  the  masto-mandibular 
line;  behind,  the  external  ear  and  sterno-mastoid  muscle;  in  front,  by  the  masseter 
muscle  ;  deeply,  it  embraces  the  styloid  processes  and  internal  carotid  artery. 
The  gland  contains  the  seventh  nerve  and  the  auriculo-temporal  branch  of  the 
fifth  nerve,  both  of  which  furnish  it  with  nerve -filaments.  It  contains  the  external 
carotid  artery,  which  here  breaks  up  into  the  temporal,  internal  maxillary,  and 
transverse  facial  branches  ;  these  supply  the  gland  with  blood.  It  contains  the 
temporo-maxillary  vein.  The  fascial  covering  of  the  gland  is  called  the  parotid 
fascia.  The  gland  is  the  largest  of  the  salivary  glands,  and  has  an  excretory 
duct  called  Stenson's. 

12.  Trace  Stenson's  duct. 

It  crosses  the  masseter  muscle  in  a  line  from  the  lobule  of  the  ear  to  the 
upper  lip.  It  perforates  the  buccinator  muscle,  and  opens  into  the  vestibule  of 
the  cavum  oris  opposite  the  second  upper  molar  tooth. 

13.  Where  does  the  facial  nerve  escape  from  the  cranium  ? 

It  escapes  through  the  stylo-mastoid  foramen,  in  the  petrosa  of  the  temporal 
bone.  On  its  escape  it  gives  off  the  posterior  auricular,  the  digastric,  and  stylo- 
hyoid  branches.  It  subsequently  forms  the  pes  anserinus,  from  which  the 
muscles  of  expression  are  innervated.  The  facial  is  a  motor  nerve. 

NOTE. — Many  a  good  dentist  has  been  heard  to  tell  his  patient,  "All  this 
toothache  is  caused  by  the  facial  nerve."  The  facial  nerve  makes  you  smile  when 
you  hear  such  things  ;  it  is  the  fifth  nerve  that  is  concerned  in  toothache. 


THE  NECK.     SUPERFICIAL  DISSECTION. 

Locate  on  the  cadaver : 

1.  The  lower  border  of  the  mandible  and  its  angle. 

2.  The  mastoid  process  of  the  temporal  bone,  behind  the  ear. 

3.  The  sterno-clavicular  articulation.      Does  it  move? 

4.  The  interclavicular  or  suprasternal  notch.      How  deep? 

5.  The  acromio-clavicular  articulation.      Does  it  move? 

6.  An  imaginary  line  from  the  angle  of  the  jaw  to  the  mastoid. 

7.  The  sterno-cleido-mastoid  muscle  and  its  double  origin. 

8.  The  exact  anterior  border  of  sterno-cleido-mastoid. 

9.  The  exact  posterior  border  of  sterno-cleido-mastoid. 
10.  The  cervical  mid-line — mento-sternal  line. 


44  PRACTICAL  ANATOMY. 

1 1.  The  hyoid  bone  in  the  mid  mento-sternal  line. 

1 2.  The  body  of  the  hyoid  bone,  one-half  of  an  inch  long  to  touch. 

13.  The  greater  horn  of  the  hyoid  -{-  lingual  artery  above  same. 

14.  The  thyroid  cartilage — Adam's  apple — and  notch  above, 
i  5 .  The  thyro-hyoid  space  +  thyro-hyoid  membrane. 

1 6.  The  thyroid  notch  -f-  mid-part  of  thyro-hyoid  membrane. 

17.  The  crico-thyroid  membrane  in  crico-thyroid  space. 

18.  The  cricoid  cartilage  and  trachea.     (Fig.  27.) 

INCISIONS. 

1 .  Through  the  mid  mento-sternal  line. 

2.  From  symphysis  menti  to  mastoid  process. 

3.  From  sternum  to  acromion  process. 

BOUNDARIES  OF  THE  NECK. 

1 .  Anterior. — -The  mid  mento-sternal  line. 

2.  Posterior. — The  anterior  border  of  the  trapezius. 

3.  Inferior. — The  clavicle  and  manubrium  sterni. 

4.  Superior. — Lower  border  of  mandible  and  masto-mandibular  line. 

TRIANGLES  OF  THE  NECK.     (Fig.  21.) 

1 .  Submaxillary  or  digastric. 

2.  Superior  carotid  or  triangle  of  election. 

3.  Inferior  carotid,  tracheal,  or  triangle  of  necessity. 

4.  Occipital — not  suboccipital. 

5.  Subclavian  or  brachial  triangle. 

BOUNDARY  STRUCTURES  OF  CERVICAL  TRIANGLES.     (Fig.  23.) 

1 .  The  sterno-cleido-mastoid  muscle. 

2.  The  mid  mento-sternal  line. 

3.  The  lower  border  of  the  mandible. 

4.  The  masto-mandibular  line. 

5.  The  omo-hyoid  muscle. 

6.  The  digastric  muscle. 

7.  The  stylo-hyoid  muscle. 

8.  The  manubrium  sterni  and  clavicle. 

SURGICAL  AND  MEDICAL  AREAS  OF  THE  NECK. 

Larynx — intubation  and  laryngotomy. 

Trachea — tracheotomy,  high  and  low. 

Thyroid  gland — operations  on. 

The  contents  of  the  carotid  sheath. 

The  subclavian  artery  and  its  branches. 

The  brachial  and  cervical  plexuses. 

The  apex  of  the  lung,  one  and  one-half  inches  above  the  first  rib. 

Traclical  and  bronchial  respiration. 

The  superficial  lymphatic  glands.     (Fig.  23.) 

The  upper  set  of  deep  lymphatic  glands. 

The  low  i-  sc/  of  deep  'lymphatic  glands. 


THE  HEAD  AND  NECK.  45 


SPECIFIC  BOUNDARIES  OF  CERVICAL  TRIANGLES.     (Fig.  23.) 

1.  Digastric  Triangle. — Mandible  and  masto-mandibular  line  ;    anterior  belly 
of  digastric  muscle  ;   posterior  belly  of  digastric  muscle  and  stylo-hyoid  muscle. 

2.  Superior  Carotid  Triangle. — Sterno-cleido-mastoid  muscle  ;  anterior  belly 
of  omo-hyoid  muscle  ;  stylo-hyoid  muscle  and  posterior  belly  of  digastric  muscle. 

3.  Inferior  Carotid  or   Traclieal  Triangle. — Mid  mento-sternal   line  ;    sterno- 
cleido-mastoid  muscle  ;   anterior  belly  of  omo-hyoid  muscle. 

4.  The  Occipital  Triangle. — The  trapezius  muscle;   the  posterior  belly  of  the 
omo-hyoid  muscle  ;  the  sterno-mastoid  muscle. 

5.  'The  Subclaman  Triangle. — The  clavicle  ;   the  posterior  belly  of  the  omo- 
hyoid  muscle  ;  the  sterno-cleido-mastoid  muscle. 

Note  that  the  sterno-mastoid  divides  the  neck  into  two  triangles.  Of  these 
two  the  anterior  contains  three,  the  posterior  two,  smaller  triangles. 

Dissection    to   sJwiv  superficial  structures    in    the  superficial  fascia   of  tJie    neck, 
as  follou'S  : 

1 .  The  platysma  myoides  muscle — a  dermal. 

2.  The  anterior  jugular  vein  is  in  front  of  sterno-mastoid. 

3.  The  posterior  jugular  vein  is  behind  the  sterno-mastoid. 

4.  External  jugular  vein  crosses  the  sterno-mastoid. 

5.  The  superficial  lymphatics — vertical  group.      (Fig.  23.) 

6.  The  superficial  lymphatics — transverse  group.      (Fig.  23.) 

7.  The  inframandibular  branch  of  the  seventh  nerve.     (Fig.  22.) 

8.  The  superficial  cervical  nerve,  of  cervical  plexus.      (Fig.  22.) 

9.  The  great  auricular  nerve,  of  cervical  plexus.      (Fig.  22.) 

10.  The  small  occipital  nerve,  of  cervical  plexus.      (Fig.  22.) 

11.  The  suprasternal  nerve,  of  cervical  plexus.      (Fig.  22.) 

12.  The  supraclavicular  nerve,  of  cervical  plexus.     (Fig.  22.) 

13.  The  supraacromial  nerve,  of  the  cervical  plexus.      (Fig.  22.) 

The  platysma  myoides  (Fig.  14)  is  a  dermal  muscle.  It  is  allied  to  the 
muscles  of  expression  and  to  the  three  dermal  aural  muscles  ;  they  are  all  rem- 
nants in  man  of  the  great  panniculus  carnosus.  To  expose  this  muscle  it  will 
be  necessary  to  exercise  the  greatest  care  in  removing  the  skin.  Usually  the 
fibres  of  origin  of  this  muscle  extend  two  .inches  below  the  clavicle.  They  are 
continued  obliquely  upward  and  forward  onto  the  face.  In  some  persons  this 
muscle  is  very  heavy  ;  in  others  it  is  almost  absent. 

The  Superficial  Nerves  of  the  Cervical  Plexus  and  the  Spinal  Accessory 
Nerve. — Dissection. — Locate  the  posterior  border  of  the  sterno-cleido-mastoid 
muscle.  Very  carefully  cut  the  platysma  along  this  posterior  border,  using  the 
forceps  for  a  director.  Next  cut  through  the  deep  fascia  along  the  posterior  border 
of  the  muscle.  Now  look  first  for  a  small  nerve  that  parallels  the  posterior  border 
of  the  sterno-cleido-mastoid  muscle.  (Fig.  '22. )  This  is  the  lesser  occipital. 
Trace  it  upward,  as  in  the  figure. 

Three  nerves  cross  the  sterno-cleido-mastoid:  (i)  The  mastoid  branch,  or 
second  small  occipital  ;  (2)  the  great  occipital ;  (3)  the  superficial  cervical. 

Follow  their  branches  out,  taking  care  to  harm  no  veins.  These  are  the 
three  ascending  branches  of  the  plexus. 

The  spinal  accessory  nerve  is  sometimes  the  subject  of  surgical  procedure. 
On  the  living,  if  you  are  in  doubt  as  to  whether  you  have  the  spinal  accessory 
or  some  other  nerve,  remember  this  rule :  Pinch  the  nerve  with  the  forceps,  and 
if  it  is  the  spinal  accessory  you  have,  the  trapezius  muscle  will  elevate  the 
shoulder-blade.  The  other  nerves  that  this  one  is  sometimes  mistaken  for  are 
all  sensory,  and  will,  if  pinched,  produce  no  muscular  contraction. 


46  PRACTICAL   ANATOMY. 

The  descending  branches  of  the  cervical  plexus  are  (i)  the  suprasternal, 
(2)  the  supraclavicular,  (3)  the  supraacromial.  Trace  these  out,  as  in  figure  22. 

Note  that  the  superficial  cervical  branch  passes  behind  the  external  jugular 
vein  ;  that  it  is  distributed  to  almost  the  entire  front  of  the  neck  ;  that  it  anasto- 
moses above  with  the  inframandibular  branch  of  the  seventh  nerve  and  below 
with  the  suprasternal. 

Note  the  spinal  accessory  nerve  pierces  the  tapezius  muscle,  and  has  many 
communications  with  the  other  nerves  in  the  occipital  triangle.  To  this  fact  is 


POSTERIOR 
A  URICULAR 

NERVE 


FACIAL  NERVE 


AURICULAR  BR.  OF 

ORE  A  T  A  URICULAR 


INFRAHANVIBULAR 


SUPERFICIAL  CERVICAL 
BRANCHES  OF  SUPER- 
FICIAL CERVICAL 
NER  VE 


SUPRASTERNAL 


)  BRANCHES  OF 
}-         GREA  T 
\     AURICULAR 

C  RE  AT  OCCIPITAL 


LESSER  OCCIPITAL 


GREAT  AURICULAR 
MASTOID  BR.  OH  2nd 

SMALL  OCCIPITAL 
SPI.VAL  ACCESSORY 

TWIGS  FROM  THE 
.VASTOID  BRANCU 

BR.   TO  LKVATOR 

A\<;ri.i  si-AWLji 

SI' PR  A- A  CROMIAL 
Sl'PRACLAVICCLAR 


BRANCHES  TO 

TR  APEX  I  US 


si     8OPBACU.rtC1tLAM 


FIG.  22. — SUPERFICIAL  BRANCHES  OF  THE  CERVICAL  PLEXUS.     (After  Hirschfeld  and  Leveille.) 


possibly  due  the  twitching  of  the  shoulder  in  frostbitten  ears  ;  purely  a  reflex 
movement.  (Fig.  22.) 

The  Superficial  Lymphatic  T. — This  will  enable  you  to  remember  the 
general  distribution  of  the  superficial  lymphatic  glands  in  the  neck.  (Fig.  23.) 
In  the  main  the  lymphatics  follow  the  veins.  They  are  readily  seen  win  11 
enlarged  by  disease  ;  they  are  scarcely  recognizable  in  cadavers  when  not  diseased. 

The  jugular  veins  (Fig.  18)  in  the  superficial  fascia  are  :  (i)  The  anterior, 
near  the  mid  inento-sternal  line.  It  opens  into  the  *iibela:>ian  rein  or  into  the 
external  jugular  under  the  stcrno-cleido-mastoid  muscle.  (2)  The  posterior  jugular 


THE  HEAD  AND  NECK. 


47 


vein  parallels  the  posterior  border  of  the  sterno-cleido-mastoid  muscle.  It  opens 
into  the  external  jugular  vein.  (3)  The  external  jugular 'vein  crosses  the  sterno- 
cleido-mastoid  muscle.  It  is  formed,  as  you  must  show,  by  the  confluence  of 
(i)  the  temporo-maxillary,  (2)  the  posterior  auricular  and  facial  communicating 
branch. 


THE    DEEP   CERVICAL    FASCIA. 

I  desire  the  student  to  have  a  conception  of  the  deep  fascia  of  the  neck,  in 
advance  of  his  work.  The  following  scheme  will  greatly  assist  him  both  in 
review  and  during  the  dissection. 

i .  The  deep  fascia  ensheathes  the  contents  of  the  neck  in  four   strata.     The 


Horizontal  ramus  of 
lymphatic  T 


Vertical  ramus  of 
lymphatic  T 


, 

FIG.  23. — SUPERFICIAL  LYMPHATICS. 

student  is  expected  to  learn   just  what  structures  are  ensheathed  by  each   layer 
of  fascia. 

2.  The  deep  fascia  has  superior  attachments,  relations,  and  specializations  ; 
it  also  has  inferior  attachments  and  continuations,  thoracic  and  maxillary,  which 
the  student  must  learn  if  he  ever  expects  to  dissect  the  neck  and  thorax  under- 
standingly. 

3.  The  deep  fascia  forms  septa  and  sheaths,  the  rationale  of  which  must  be 
read   and   studied   in  the   introductory  chapter  of  this   book.     The   deep  fascia 
here,  as   in  every  region  of  the   body,  belongs  to  the  dense  compact  variety  of 
connective  tissue. 


48  PRACTICAL   ANATOMY. 

4.  The  deep  fascia  determines  the  course  taken  by  pus  and  missiles,  hence  a 
thorough  knowledge  of  the  architecture  of  the  deep  fascial  envelopes  of  the 
neck  is  just  as  important  as  any  fascial  area  in  the  body. 

Figure  24  represents  schematically  a  transverse  section  of  the  neck.  From 
this  it  will  be  seen  there  are  two  spaces:  (i)  Those  formed  by  delamina- 
tion  of  the  four  layers,  including  certain  structures  and  their  nerve-supply  and 
blood-supply.  (2)  The  interfascial  spaces  containing  fat  and  connective  tissue. 
It  will  be  seen  that  the  first  layer  delaminates  to  unsheath  the  sterno-rnastoid 
muscle.  The  second  layer  delaminates  to  enclose  the  omo-hyoid,  sterno-hyoid, 
sterno-thyroid,  and  thyro-hyoid  muscles,  with  their  nerve -supply  and  blood- 
supply.  The  third  layer  delaminates  to  enclose  the  larynx  and  trachea  and 
thyroid,  the  pharynx  and  oesophagus,  the  carotid  sheath  and  its  contents.  The 
fourth  layer  delaminates  to  ensheath  the  rectus  capitis  anticus  major  and  minor 
and  longus  colli  muscles. 

First  layer 


Second  layer 


Third  layer 


Fourth  layer 


FIG.  24. — DEEP  CERVICAL  FASCIA — TRANSVERSE  SECTION.     (Schematic.) 

Dissection  : 

1.  The  temporal  muscle  and  its  aponeurosis  or  fascia. 

2.  The  masseter  muscle  and  its  aponeurosis  or  fascia. 

3.  The  sterno-cleido-mastoid  and  its  fascial  covering. 

4.  The  trapezius  muscle  and  its  aponeurosis. 

5.  The  zygoma,  and  its  relations. 

6.  The  temporal  fossa  and  its  contents. 

7.  The  temporal  ridge,  its  formation  of  three  parts. 


Examine  your  work  and  answer  this  quiz  : 

1.  Name  the  deep  fascia  covering  the  temporal  muscle  and  give  all  its  attach- 
ments. 

It  is  called  the  temporal  fascia.  It  is  attached  to  the  linea  suprema  of  the 
complete  temporal  ridge,  and  to  the  superior  border  of  the  zygomatic  arch. 

2.  What  does  the  complete  temporal  ridge  consist  of  Y 

It  consists  of  two  parallel  lines,  having  a  frontal,  a  parietal,  and  a  temporal 
portion.  The  aponeurosis  of  the  muscle  arises  from  the  upper,  the  muscle  itself 
from  the  lower  line. 

3.  \Vhat  structures  occupy  the  superficial  fascia,  covering  the  temporal  muscle  / 
The  superficial  temporal  arteries  and  their  veins  ;  the  auriculo-temporal  nerve,  a 

branch  of  the  fifth  cranial  ;  some  temporal  brandies  of  the  seventh  or  facial  nerve, 
and  the  lesser  occipital  nerve. 


THE  HEAD  AND  NECK.  49 

4.  Wliat  is  the  massctcric  fascia  ? 

The  deep  fascia  covering  the  masseter  muscle.  It  is  of  cervical  derivation, 
being,  with  the  parotid  fascia,  the  upward  continuation  of  the  first  layer  of  the 
deep  cervical  fascia. 

5.  Name  the  structures  on  tlie  masseter  muscle . 

The  parotid  gland  in  part;  the  pes  anserinus  of  the  seventh  nerve  ;  Stenson's 
duct.  In  front  of  and  under  the  anterior  part  of  the  muscle  is  some  fat,  called  in 
the  child  the  sucking  pad. 

6.  Explain  the  relations  and  composition  of  the  zygomatic  arch. 

The  arch  is  composed  of  a  malar  and  a  temporal  portion.  It  has  a  superior 
border  into  which  is  inserted  the  temporal  fascia ;  an  outer  surface  that  is 
subcutaneous  ;  an  inner  surface  and  a  lower  border  from  which  arises  the 
masseter  muscle.  Under  the  arch'  are  found  the  coracoid  process  of  the 
temporal  bone,  into  which  is  inserted  the  temporal  muscle  ;  the  sigmoid  notch, 
through  which  pass  the  arteries  and  nerves  to  the  masseter  muscle. 

7.  What  structures  lie  on,  and  posterior  to,  the  sterno-cleido-mastoid  muscle  ? 
The    muscle   is  ensheathed    by  the   first  layer  of  the  deep  cervical  fascia. 

(Fig.  24.)  On  the  muscle  lie  the  auricularis  magnus  and  the  superficial  cervical 
nerves.  The  muscle  is  crossed  by  the  external  jugular  vein.  The  spinal 
accessory  nerve  and  all  the  superficial  branches  of  the  cervical  plexus  pierce  the 
deep  fascia  at  the  posterior  border  of  the  muscle.  These  nerves  are  all  in  the 
occipital  triangle. 

8.  Describe  the  superficial  branches  of  the  cervical  plexus.     (Fig.  22.) 

They  are  seven  in  number.  The  four  ascending  branches  supply  the  neck 
and  side  of  the  head  with  sensation.  The  three  descending  branches  supply  the 
shoulder  and  upper  third  of  the  thorax.  Their  names  are  : 

1.  Lesser  occipital  parallels  the  sterno-cleido-mastoid  muscle.     It  supplies 
the  skin  over  the  temporal  muscle  and  the  upper  posterior  part  of  the  ear. 

2.  The  mastoid  branch,  or  second  small  occipital,  supplies  the  skin  over  the 
insertion  of  the  sterno-mastoid  muscle  into  the  mastoid  process  of  the  temporal 
bone. 

3.  The  great  auricular  crosses  the  sterno-mastoid  muscle  to  the  ear,  to  which 
and  to  the  skin  over  the  the  parotid  it  is  distributed. 

4.  The   superficial    cervical    nerve   crosses   horizontally   the   sterno-mastoid 
muscle.     It  supplies  with  sensation  the  whole  front  of  the  neck.      It  passes  be- 
hind the  external  jugular  vein. 

5.  Suprasternal.      This  nerve  supplies  the  skin  over  the  origin  of  the  sterno- 
mastoid  and  over  the  manubrium  sterni. 

6.  The  supraclavicular  supplies  the   skin   over  the  pectoralis  major  to  the 
nipple.      It  probably  is  this  nerve  that  may  account  for  the  very  diffuse  pain  over 
the  head,  neck,  and  shoulders  in  sore  nipples  of  nursing  mothers. 

7.  The  supraacromial  supplies  the  skin  over  the  deltoid  and  clavicular  por- 
tion of  the  trapezius  muscles. 


The  Masseter  Muscle  (Fig.  25). — Cut  this  muscle  at  its  origin  from  the 
malar  process  of  the  maxilla  and  the  inner  surface  and  lower  border  of  the 
zygoma.  As  you  turn  the  same  down,  notice  the  nerve-  and  blood-supply 
coming  through  the  sigmoid  notch.  A  little  work  with  the  forceps  will  remove 
the  fat  and  develop  the  insertion  of  the  temporal  muscle  into  the  coracoid 
process.  Find  the  masseter  inserted  into  the  outer  surface  of  the  ramus  of  the 
mandible. 


So  PRACTICAL  ANATOMY. 

The  Temporal  Muscle  (Fig.  25). — Cut  the  aponeurosis  of  this  muscle  around 
the  whole  circumference  of  the  temporal  fossa.  The  aponeurosis  will  be  attached 
to  the  zygoma  in  t\vo  layers.  Find  between  these  two  layers  a  small  branch  of 
the  temporo-malar  nerve.  The  nerve  will  do  you  no  good  ;  but  finding  the 
same  will  be  evidence  of  careful  work.  Turn  the  muscle  itself  down,  after  hav- 
ing removed  the  fascia,  and  see  the  deep  temporal  arteries.  These  supply  the 
muscle  with  blood.  They  lie  on  the  bone.  They  are  branches  of  the  internal 
maxillary.  Find  the  deep  temporal  vein  (Fig.  18)  piercing  the  fascia  above  the 
zygoma,  to  join  the  superficial  temporal. 

The  sterno-cleido-mastoid  muscle  (Fig.  25)  has  two  origins  :  (i)  A  sternal  ; 


FIG.  25. — MUSCLES  OF  THE  FACE  AND  NECK. 

I.  Frontal  muscle.  2.  Occipital  muscle.  3,  3.  Epicranial  aponeurosis.  4.  Temporal  muscle.  5.  Ketra- 
hens  aurem.  6.  Orbicularis  palpebrarum.  7.  Levator  labii  superioris  et  abeque  nasi.  8.  Dilator 
naris.  9.  Compressor  naris.  9'.  Pyramidalis  nasi.  lo.  Zygomatic  minor,  i-i.  Zygomatic  major. 
12.  Masseter.  13.  Levator  anguli  oris.  14.  Levator  labii  superioris.  15.  Orbicularis  oris.  16. 
Buccinator.  i6/.  Depressor  anguli  oris.  17.  Depressor  labii  inferioris.  18.  Levator  labii  inferi- 
oris.  19.  Sterno-mastoid.  20.  Trapezius.  21.  Digastric  and  stylo-hyoid.  22.  Anterior  belly  of 
digastric.  23.  Pulley  for  tendon  of  digastric.  24,  24.  Omo-hyoid.  25.  Sterno-hyoid.  26.  Thyro- 
hyoid.  27.  Mylo-hyoid.  28.  Splenius  capitis.  29.  Splenius  colli.  30.  Levator  anguli  scapula'. 
31.  Scalenus  posticus.  32.  Scalenus  anticus. 


(2)  a  clavicular.  Its  size,  location,  and  extensive  nerve-supply  make  it  the  most 
important  muscle  in  the  neck.  These  origins  vary  in  size.  In  some  cases  you 
will  find  the  clavicular  part  very  small,  in  other  cases  very  large.  The  sternal 
origin  corresponds  to  the  mastoid  insertion  ;  the  clavicular  origin  corresponds  to 
the  occipital  insertion.  If  you  will  follow  the  cleft  between  the  two  heads,  it 
will  lead  you  to  the  junction  between  the  occipital  and  mastoid.  (Fig.  23.) 

Stemo-mastoid  slicatli  ( Fig.  24)  is  formed  by  a  delamination  of  the  first  layer 
of  deep  cervical  fascia.  Cut  through  this  sheath  from  end  to  end,  just  as  you 
would  separate  two  muscles.  In  fact,  as. pointed  out  in  the  preceding  paragraph, 
there  are  two  muscles  here,  coalesced  to  form  one. 


THE  HEAD  AND  NECK. 


51 


NERVE-SUPPLY  OF  THE  STERNO-MASTOID. — This  muscle,  as  you  may  now  see, 
receives  numerous  twigs  from  the  spinal  accessory  nerve  as  this  nerve  is  passing 
through  the  muscle.  It  also  receives  nerves  from  the  cervical  plexus.  Lift  the 
muscle  very  carefully,  and  demonstrate  these  nerves  on  your  own  work. 

The  Upper  Attachments  and  Special  Structures  Formed  by  the  First 
Layer  of  Deep  Cervical  Fascia  (Fig.  26). — The  same  fascia  that  covers  the 
sterno-mastoid  muscle  is  continued  upward  and  forms  special  structures.  You 
will  now  dissect  and  study  these.  Cut  along  the  lower  margin  of  the  jaw  to  the 
symphysis  rnenti.  Avoid  the  facial  artery  and  vein  in  front  of  the  masseter 
muscle. 

Distribution  of  the  Deep  Cervical  Fascia  Above  (Fig.  26). — You  now 
see  this  fascia  extending  from  the  sterno-mastoid  muscle  to  the  masseter  muscle 


Capsule  for 
submaxil- 
lary gland 


Sheath  for  di- 
gastric muscle 


Sheath  for  the  de- 
pressors of  the 
hyoid  bone 


Mandibular  attachment 


Masseteric  fascia 


Parotid  fascia 


Stylo-mandibular 
ligament 


Sheath  for  the 
sterno-mastoid 


The  carotid 
sheath 


Sterno-mastoid, 
cut 


Trapezius 


—      Scalenus  posticus 


Scalenus  medius 


Scalenus  anticus 


Fi<;.  26. — SCHEME  OF  UPPKR  ATTACHMENTS  OF  AND  SPECIAL  NAMKS  FOR  DEEP  CERVICAL  FASCIA. 


and  parotid  gland,  forming  their  specific  fasciae.  You  see  it  extending  from  the 
styloid  process  to  the  jaw  as  the  stylo-maxillary  ligament ;  you  see  it  forming  a 
capsule  for  the  submaxillary  gland,  and  continuing  forward  to  invest  the  anterior 
belly  of  the  digastric  muscle. 

The  submaxillary  gland  is  ensheathed  by  the  first  layer  of  deep  cervical 
fascia.  Observe  the  facial  vein  passing  in  front  of  the  gland  ;  and  the  facial 
artery,  perforating  the  deep  fascia  and  passing  behind  the  gland,  or  even  through 
the  same. 

WJiat  nerves  accompany  the  facial  artery  in  its  distribution  to  the  face  ? 

Sympathetic  branches — the  nervi  molles.  They  produce  blushing  and  pallor 
of  the  face. 


52  PRACTICAL  ANATOMY. 

Are  any  other  arteries  accompanied  by  sympathetic  nerves,  in  like  manner,  in  this 
region  / 

Yes,  branches  of  the  sympathetic  accompany  every  branch  of  the  external 
carotid  artery.  Hyperaemia  then  may  occur  in  the  distribution  of  the  temporal, 
internal  maxillary,  and  lingual  arteries.  The  specific  name  for  this  physiological 
hyperaemia  on  the  face  is  "  blushing." 

Relations  of  the  Sterno-cleido-mastoid  Muscle. — Review  now  carefully 
your  dissection,  and  learn  the  relations  of  this  muscle  thus  far  exposed.  See  if 
your  work  shows  the  following  points  : 

1.  Did  you   demonstrate  a  sternal  and  clavicular  origin  and  a  mastoid  and 
occipital  insertion  of  the  muscle  ? 

2.  Did  you  find  crossing  or  lying  upon  the  sheath  of  the  muscle  the  external 
jugular  vein,  the  superficial  cervical  nerve,  the   great  auricular   nerve,  and   the 


Stylo-hyoid  ligament 


BODY  OF  HYOID  BONE 
Thyro-hyoid  ligament 


Sterno-hyoid  muscle 

Omo-hyoid 

Thyro-hyoid 


Crioo-thyroid 
Sterno-thyroid 

ISTHMUS 


TRACHEA 


Thyro-hyoid  membrane 


Levator  glandulee  thyroide 

THYROID  CARTILAGE 


PYRAMIDAL  PROCESS  OF  THYROID  BODY 


LEFT  LATERAL  LOBE 


FIG.  27. — THYROID  BODY,  WITH  MIDDLE  LOBE  AND  LEVATOR  MUSCLE. 


mastoid  branch  or  second  small  occipital  nerve  ?  Did  you  see  emerging  through 
the  deep  fascia,  between  the  muscle  and  the  trapezius,  in  the  occipital  triangle, 
the  spinal  accessory  nerve  and  all  the  superficial  branches  of  the  cervical  plexus  ? 
Did  you  find  the  sheath  of  the  muscle  attached  to  the  clavicle  below  ?  Did  you 
find  the  same  derived  from  the  first  layer  of  the  deep  cervical  fascia  and  continu- 
ous above  with  the  masseteric  and  parotid  fasciae  ?  with  the  stylo-maxillary  liga- 
ment? with  the  submaxillary  and  digastric  fasciae? 

Having  done  this,  you  may  lift  the  muscle,  observe  its  nerve-supply  again, 
from  the  spinal  accessory  and  cervical  plexus,  and  study  the  posterior  relations. 

Interior  relations  of  t lie  stcrno-clcido- mastoid  muscle  are  : 

1.  The  contents  of  the  second  layer  of  the  deep  cervical  fascia. 

2.  The  carotid  sheath   and  its   contents.     This   latter,  you  will  remember, 
belongs  to  the  third  layer  of  deep  cervical  fascia. 


THE  HEAD  AND  NECK. 


53 


THE  MUSCLES  AND  NERVES  IN  THE  SECOND  LAYER  OF  DEEP  CERVICAL  FASCIA. 

1 .  The  sterno-hyoid  and  omo-Jiyoid. 

2.  The  sterno-thyroid  and  thyro-hyoid. 

3.  The  nerve-supply  of  these — the  ansa  liypoglossal  loop.     (Figs.  23  and  29.) 
Having  turned  the  sterno-mastoid  muscle  and  the  fascia  extending  from  it  to 

the  mid-line  of  the  neck  aside,  you  expose  the  sterno-hyoid  and  the  omo-hyoid 
of  this  group.  Figure  27  shows  you  the  insertion  of  these  two  muscles  con- 
jointly into  the  lower  border  of  the  body  of  the  hyoid  bone.  Cut  these  two 
muscles  one  inch  below  this  insertion,  turn  the  lower  part  of  the  same  forward 
carefully,  and  note  the  nerve-supply.  These  muscles  must  be  handled  very  care- 
fully, in  order  to  preserve  them  and  also  their  nerves.  The  omo-hyoid  arises 
from  the  superior  border  of  the  scapula  for  one  inch.  The  sterno-hyoid  arises 


Facial  artery 


Lingual  artery 


Supra-hyoid  branch 
Infra-hyoid  branch 

Superior  laryngeal  branch 


Crico-thyroid  branch 


External  carotid  artery 

—  Ascending pharyngeal  artery 

Internal  carotid  artery 


Sterno-mastoid  branch 


Superior  thyroid  artery 


Common  carotid  artery 


Inferior  thyroid  artery 


FIG.  28. — SCHEME  OF  SUPERIOR  THYROID  ARTERY. 


from  the  manubrium  sterni.  Trace  out  these  origins  at  a  later  stage  of  your 
work. 

The  sterno-cleido-thyroid  is  commonly  called  sterno-thyroid.  This  is  inserted 
into  the  oblique  line  of  the  ala  of  the  thyroid  cartilage.  (Fig.  27.)  From  here 
it  is  continued  to  the  lower  border  of  the  outer  third  body,  and  the  inner  half  of 
the  greater  horn  of  the  hyoid  bone  as  the  thyro-hyoid  muscle. 

The  sterno-thyroid  arises  from  the  manubrium  low  down,  and  also  from  the 
clavicle.  (Fig.  30.)  Detach  this  muscle  from  its  insertion  and  turn  it  down 
very  carefully,  and  you  will  see  the  thyroid  gland  and  its  isthmus. 

The  thyro-hyoid  removed  by  detaching  it  at  its  origin,  you  expose  the  thyro- 
hyoid  membrane,  and  see  entering  the  same  the  superior  laryngeal  nerve  and 
artery.  (Fig.  28.) 


lOkvury  Body 


12 ™  Nerve, - 

HypoglossaJ 

(Nonus  or9'KofWUis.) 


foSterno  tljroul, Sthynut 
ma-lyout . 


FIG.  29. — THE  LOOP  FORMED  BY  COMMUNICATING  BRANCHES. 


Sterno-thyroid 


Triangularis 
sterni 


Sternal  origin 
of  diaphragm 


Costal  origin 
of  diaphragm 


Sterno-hyoid 


Triangular!* 
Bterni 


Transveraalis  abdominis 

FIG.  30. — 'I'm    MTSCI.KS  ATTACIIKD  TO  mi.  HACK.  01    THE  SIKRMM. 

54 


THE   HEAD  AND  NECK.  55 

THE  NERVE-SUPPLY  TO  THE  DEPRESSOR  MUSCLES  OF  THE  HYOID  BONE. — The 
group  you  have  just  dissected  comes  from  a  loop  called  the  ansa  hypoglossal. 
The  expression  cervico-Jiypoglossal  would  be  a  better  term,  as  it  would  seem,  as 
it  expresses  the  derivation  of  the  two  elements  composing  the  loop.  (Fig.  29.) 

The  loop  is  formed  by  the  descendens  hypoglossi,  anastomosing  with  two 
communicating  branches  from  the  deep  part  of  the  cervical  plexus.  This  loop 
is  formed  on  the  front  part  of  the  carotid  sheath.  From  it  branches  are  given  off 
to  the  depressors  of  the  hyoid  bone. 


1 .  Give  the  boundaries  of  tJiat  part  of  the  neck  most  frequently  operated  on  by 
the  surgeon. 

Anteriorly,  the  mid-  or  mento-sternal  line.  Posteriorly,  the  anterior  border 
of  the  trapezius  muscle.  Superiorly,  the  mandible  and  masto-mandibular  line. 
Inferiorly,  the  clavicle  and  interclaviculaf  ligament. 

2.  Name  the  cervical  triangles  and  indicate  tlieir  importance. 

The  submaxillary  or  supra-hyoid  triangle  is  bounded  above  by  the  mandible 
and  masto-mandibular  line  ;  below,  by  the  digastric  and  stylo-hyoid  muscles  ; 
in  front,  by  the  mento-sternal  line.  It  contains  :  (i)  The  facial  vessels  and  their 
sympathetic  nerves  ;  (2)  the  submaxillary  gland,  its  blood-vessels,  nerves,  and 
capsule ;  (3)  the  submental  and  mylo-hyoid  vessels  and  nerves  ;  (4)  the  stylo- 
mandibular  ligament ;  (5)  the  parotid  gland  and  its  contents  ;  (6)  the  vagus 
nerve,  internal  jugular  vein,  internal  and  external  carotid  arteries. 

The  superior  carotid  triangle  is  bounded  above  by  the  digastric ;  below,  by 
the  omo-hyoid  ;  behind,  by  the  sterno-mastoid  muscle.  It  contains:  (i)  The 
common  carotid  artery  ;  (2)  the  external  carotid  artery  ;  (3)  the  internal  jugular 
vein  ;  (4)  the  vagus  ;  (5)  spinal  accessory,  and  (6)  sympathetic  nerves. 

3.  The  inferior  carotid  or  tracheal  triangle  is  bounded  above  by  the  omo- 
hyoid,  behind  by  the  sterno-mastoid,   in  front  by  the   mento-sternal   line.     It 
contains  :   (i)  The  thyroid  gland  and  its  blood-supply  ;    (2)  the  trachea;   (3)  the 
carotid  sheath  and  contents  ;  (4)  the  inferior  laryngeal  nerve  and  inferior  thyroid 
vessels. 

The  three  foregoing  triangles  lie  anterior  to  the  sterno-mastoid  muscle.  The 
two  following  ones  lie  posterior  to  the  sterno-mastoid  muscle. 

4.  The  occipital  triangle  is  bounded  in  front  by  the  sterno-mastoid,  behind  by 
the  trapezius,  below  by  the  omo-hyoid   muscle.      It  contains:    (i)  The  spinal 
accessory  nerve;    (2)   the  descending  branches  of  the  cervical  plexus;  (3)  the 
transversalis  colli  vessels  ;  (4)  a  chain  of  lymphatic  glands. 

5.  The  subclavian  triangle  is  bounded  in  front  by  the  sterno-mastoid,  above 
by   the   omo-hyoid,   below   by   the   clavicle.      It   contains:    (i)  The   subclavian 
artery  and  vein  ;  (2)  the  brachial  plexus  ;  (3)  the  external  jugular  vein  ;  (4)  the 
nerve  to  the  subclavian  muscle. 

The  student  will  please  note  that  any  arbitrary  classification  of  contents  is 
impossible.  Structures  are  found  to  form  partial  contents  of  several  triangles. 
The  surgical  triangles  are  to  the  modern  surgeon  about  what  totem  poles  would 
be  to  the  city  council. 

6.  Name  the  structures  in  the  superficial  fascia  of  the  neck. 

(i)  The  platysma  myoides  muscle  ;  (2)  the  anterior,  external,  and  posterior 
jugular  veins  ;  (3)  the  inframandibular  branch  of  the  seventh  nerve,  and  (4)  the 
superficialis  colli  branch  of  the  cervical  plexus. 

7.  Name  the  layers  of  deep  cervical  fascia  and  give  the  contents  of  each. 
The  first  layer  surrounds  the  sterno-mastoid  muscle. 


56  PRACTICAL  ANATOMY. 

The  second  layer  surrounds  the   hyoid   depressors  and  their  vessels  and. 
nerves. 

The  third  layer  surrounds  the  larynx,  trachea,  thyroid,  oesophagus,  common 
carotid  artery,  internal  jugular  vein,  and  vagus  nerve. 

The  fourth  layer  covers  the  rectus  capitis  anticus  major  and  minor  muscles 
and  the  longus  colli. 

8.  What  becomes  of  the  first  and  second  layers  below? 
They  are  attached  to  the  clavicle  and  sternum. 

9.  Give  the  origin  and  insertion  of  the  temporal  muscle. 

This  muscle  arises  from  the  complete  temporal  ridge,  from  the  temporal 
aponeurosis,  from  the  temporal  fossa,  and  is  inserted  into  the  coronoid  process 
of  the  mandible. 

10.  Analyze  the  coronoid  process. 

This  has  an  outer  and  an  inner  surface,  an  anterior  and  a  posterior  border,  a 
base,  and  an  apex. 

11.  Of  what  does  the  complete  temporal  ridge  consist  ? 

It  consists  of  frontal,  parietal,  and  temporal  portions.  The  ridge  has  a 
superior  part  for  the  attachment  of  the  temporal  fascia  ;  an  inferior  part  for  origin 
of  the  muscle. 

1 2.  What  do  you  find  in  grooves  on  the  deep  surface  of  the  muscle  next  the  bone  ? 
The  deep  temporal  arteries — branches  of  the  internal  maxillary  artery — for 

the  supply  of  the  muscle. 

1 3.  Analyse  the  zygomatic  arch  and  tell  what  you  find  under  fke  same. 

The  arcus  zygomaticus  is  made  up  of  the  zygomatic  processes  of  the  malar 
and  temporal  bones.  It  has  a  superior  border,  into  which  is  inserted  the  tem- 
poral fascia  ;  an  outer  surface,  which  is  subcutaneous  ;  an  inferior  border  and  an 
inner  surface,  which  are  occupied  by  the  origin  of  the  masseter  muscle.  Under 
the  arch  are  the  coronoid  and  condylar  processes  of  the  mandible  ;  the  sigmoid 
notch,  transmitting  the  masseteric  vessels  and  nerves  ;  the  external  pterygoid 
muscle ;  and  a  considerable  quantity  of  fatty  connective  tissue. 

1 4.  Describe  the  masseter  muscle. 

This  muscle  arises  ( i )  from  the  inferior  border,  anterior  two-thirds,  and  (2)  from 
the  inner  surface  and  posterior  one-third  of  the  lower  border  of  the  zygomatic 
arch.  It  is  inserted  into  the  external  surface  of  the  ramus.  It  is  covered  on  its 
outer  surface  by  the  masseteric  fascia,  on  which  lie  the  pes  anserinus,  the  parotid 
gland  in  part,  and  Stenson's  duct. 

1 5 .  Describe  the  stcrno-clcido-mastoid  muscle. 

This  muscle  has  two  origins — a  clavicular  and  a  sternal ;  and  two  insertions 
— a  mastoid  and  an  occipital.  It  extends  obliquely  across  the  neck,  dividing  this 
region  into  an  anterior  and  a  posterior  part.  Its  nerve-supply  is  from  the  spinal 
accessory  and  deep  branches  from  the  cervical  plexus.  It  lies  on  the  carotid 
sheath  in  part  of  its  course,  and  along  its  posterior  margin  emerge  the  superficial 
branches  of  the  cervical  plexus.  (Fig.  22.) 

1 6.  Name  t/ic  superficial  brandies  of  tlic  cervical  plexus. 

The  descending  branches  are  the  suprasternal,  supraacromial,  supra- 
clavicular  ;  the  ascending  branches  are  the  great  auricular,  the  small  occipital, 
the  lesser  occipital,  and  the  superficialis  colli. 

Quiz  on  the  Structures  in  the  Second  Layer  of  Deep  Cervical  Fascia. 

1.  Name  the  depressor  muscles  of  t/ic  liyoid. 

(i)  The  sterno-hyoid.  (2)  The  omo-hyoid.  (3)  The  sterno-thyroid.  (4)  The 
thyro-hyoid. 

2.  /fo:,<  are  tlicsc  muscles  cnshcathcd  and  from  elicit  are  they  separated  in  front 
and  behind  ? 

They  are  ensheathed  by  a  delamination  of  the  second  layer  of  deep  cer- 


THE   HEAD  AND  NECK.  57 

vical  fascia.  In  front  of  them  is  the  first  layer  of  deep  cervical  fascia,  which 
delaminates  on  the  side  of  the  neck  to  enclose  the  sterno-cleido-mastoid  muscle. 
Behind  these  structures  are  the  members  making  up  a  group  ensheathed  by  the 
third  layer  of  deep  cervical  fascia. 

3.  To  what  did  you  find  the  second  layer  of  deep  cervical  fascia  attached  supe- 
riorly and  inferiorly  ? 

Superiorly  it  was  attached  to  the  hyoid  bone ;  inferiorly  to  the  posterior 
part  of  the  clavicle  and  manubrium. 

4.  From  what  source  do   the  depressors  of  the  hyoid  bone  receive  their  nerve- 
supply  / 

From  the  ansa  hypoglossal  loop,  descendens,  and  communicans  noni. 

5 .  Hoiv  is  the  ansa  liypoglossal  loop  formed  ? 

It  is  formed  by  the  union  of  two  branches  from  the  deep  cervical  plexus 
with  one  branch  from  the  hypoglossal  nerve. 

6.  What  are  these  communicating  nerves  called  ? 

The  one  from  the  hypoglossal  nerve  is  called  the  descendens  Jiypoglossi ;  the 
two  from  the  cervical  plexus  are  called  the  communicantes  hypoglossi,  and  the 
loop  formed  by  their  union  is  the  hypoglossal  loop. 

j.   Have  these  communicating  nerves  any  synonyms  in  anatomical  literature  ? 

Yes,  in  the  older  texts  they  are  called  the  descendens  noni  and  communi- 
cantes noni.  Under  the  classification  of  cranial  nerves  by  Willis,  there  were  nine 
pairs.  The  hypoglossal  belonged  to  this  ninth  pair,  hence  the  expressions  nervus 
nonus,  nervus  descendens  noni,  and  nervi  communicantes  noni. 

8.  Can  you  think  of  a  compound  word  that  would  be  more  specific,  and  at  the 
same  time  a  more  rational  name  than  ansa  hypoglossal  ? 

Yes,  the  compound  cervico-hypoglossal  would  express  the  anatomical  parties 
to  the  compound,  and  would  harmonize  with  our  rules  for  writing  compound 
words,  by  which  such  relations  should  always  be  expressed. 

9.  Where  did  you  find  this  loop  ? 

On  the  sheath  containing  the  common  carotid  artery,  pneumogastric  nerve, 
and  internal  jugular  vein.  (Fig.  31.) 


The  third  layer  of  deep  cervical  fascia  contains  (Fig.  24) : 

1.  The  thyroid  body — its  nerve-supply  and  vessels. 

2.  The  larynx  and  trachea,  nerves  and  vessels. 

3.  The  common  carotid  artery,  vagus  and  internal  jugular  vein. 

4.  The  external  carotid  artery  and  its  branches  in  the  neck. 

5.  The  cervical  stage  of  the  internal  carotid  artery. 

6.  The  hypoglossal  nerve  and  its  descending  branch. 

7.  The  cervical  sympathetic  cord  and  ganglia. 

8.  The  arteries  from  the  transverse  aorta  and  their  branches. 

9.  The  phrenic  nerve  and  anterior  scalenus  muscle. 

10.  The  cervical  plexus  and  its  branches  of  origin. 

1 1 .  The  bracldal  plexus  and  its  sheath. 

12.  The  scaleni  muscles — anticus,  medius,  posticus. 

Dissection. — Remove  the  group  of  muscles  in  the  second  layer  of  the  cervical 
fascia,  and  examine  the  structures  in  the  following  order  : 

i.  Thyroid  Gland  (Figs.  27  and  28). — This  derives  its  capsule  from  the  con- 
nective tissue  in  which  it  is  developed.  It  has  two  lobes,  connected  by  an  isthmus. 
Its  arteries  are  a  superior  thyroid,  which  you  will  take  to  its  origin,  the  external 
carotid.  This  artery  is  attended  by  a  vein.  Note  the  anastomosis  between  the 
5 


58  PRACTICAL  ANATOMY. 

superior  thyroid  and  the  inferior  thyroid  in  the  substance  of  the  gland.  The 
inferior  thyroid  artery  is  a  branch  of  the  thyroid  axis  of  the  subclavian.  Note 
the  crico-thyroid  branch  on  the  crico-thyroid  membrane.  Note  also  the  superior 
laryngeal  artery,  the  same  artery  you  found  when  you  removed  the  thyro-hyoid 
muscle  :  it  accompanies  the  superior  laryngeal  nerve.  The  thyroid  gland  belongs 
to  the  class  of  ductless  structures,  as  the  spleen,  thymus,  and  suprarenal  capsules. 
An  enlargement  of  this  gland  is  called  bronchocele ;  in  which  case  the  isthmus 
may  be  divided  or  one-half  of  the  gland  removed.  The  nerves  to  the  thyroid 
are  of  sympathetic  derivation,  from  the  middle  and  inferior  cervical  ganglia.  The 
inferior  thyroid  veins  you  will  trace  to  the  left  brachio-cephalic  vein.  -The 
superior  and  middle  veins  open  into  the  internal  jugular  vein.  These  veins  take 
their  origin  in  a  plexus  of  veins  especially  large  on  the  posterior  part  of  the  gland. 

The  carotid  sheath  is  situated  by  the  side  of  the  trachea  and  larynx.  In 
this  sheath  are  the  common  carotid  artery  internally,  the  internal  jugular  vein 
externally,  and  the  pneumogastric  or  vagus  nerve  between  the  two. 

The  internal  jugular  vein  is  formed  by  the  confluence  of  the  dural  sinuses. 
These  sinuses  receive  their  blood  from  the  brain.  The  internal  jugular  veins  are 
made  up  at  the  jugular  foramina  at  the  base  of  the  skull.  The  ninth,  tenth, 
and  eleventh  cranial  nerves  leave  the  cranial  cavity  with' the  veins.  In  its  course 
down  the  neck  the  jugular  vein  receives  the  superior  and  middle  thyroid 
veins;  and  near  their  termination,  they  receive  the  external  jugular  veins. 
Behind  the  clavicle,  you  will  see  the  internal  jugular  vein  on  each  side  unite  with 
the  subclavian  vein.  The  result  of  this  union  is  a  large  vein,  called  the 
innominate  or  brachio-cephalic  vein.  These  latter  of  each  side  unite  with  the 
vena  azygos  major  to  form  the  descending  vena  cava. 

The  right  common  carotid  artery  begins  on  the  right  side,  at  the  bifurcation 
of  the  innominate  artery.  (Fig.  36.)  This  division  occurs  opposite  the  upper 
margin  of  the  thyroid  cartilage.  The  result  of  the  division  gives  us  an  internal 
and  an  external  carotid  artery.  Find  to  the  inner  side  of  the  common  carotid 
artery  the  larynx,  trachea,  thyroid  gland,  inferior  thyroid  artery,  and  recurrent 
laryngeal  nerve. 

The  left  common  carotid  artery  on  the  left  side  differs  from  that  on  the 
right  as  follows  :  It  is  given  off  in  the  thorax  from  the  highest  part  of  the  arch  of 
the  aorta.  (Fig.  36.)  It  has  the  same  relations  in  the  neck  as  the  right  common 
carotid.  In  the  thorax  the  left  common  carotid  artery  is  behind  the  manubrium 
sterni,  the  origins  of  the  sterno-thyroid  and  sterno-hyoid  muscles,  the  left  brachio- 
cephalic  or  innominate  vein,  and  the  remains  of  the  thymus  gland.  Behind  the 
artery  are  the  trachea,  oesophagus,  and  thoracic  duct.  Internal  to  the  artery  are 
the  innominate  artery,  the  inferior  thyroid  veins,  and  remains  of  the  thymus  gland. 
External  to  the  artery  are  the  vagus  nerve,  the  left  lung,  and  pleura. 

The  Glandulae  Concatenatse. — If  the  subject  be  tubercular,  you  may  find 
the  deep  cervical  lymphatics  enlarged.  They  lie  with  the  internal  jugular  vein, 
and  may  have  contracted  firm  adhesions  to  the  vein  or  artery  or  both.  This 
seems  to  be  the  tendency  of  glandular  tissue  :  (i)  to  penetrate  or  (2)  to  embrace. 
Instance  the  deep  part  of  the  parotid  gland,  penetrating  the  glenoid  cavity  and 
embracing  the  styloid  process  too  ;  the  anterior  part  of  the  same  gland  embraces. 
in  a  V  shape,  the  posterior  border  of  the  ramus  of  the  mandible.  Likewise, 
these  lymphatics,  when  enlarged,  embrace  vessels,  a  circumstance  which  makes 
their  removal  often  a  very  dangerous  procedure.  These  glands  you  will  find 
forming  a  continuous  chain  from  the  base  of  the  skull  to  the  apex  of  the  thorax, 
where  they  are  continuous  with  the  mediastinai  gland-chains. 

The  pneumogastric  nerve,  also  called  the  vagus,  or  par  vagum,  lies  between 
I  lie  common  carotid  artery  and  internal  jugular  vein.  Separate  the  connective 
tissue  between  the  vessels  and  find  the  nerve,  deeply  located.  This  n  r\e  gives 


77//1   HEAD  AND  NECK. 


59 


off  in  the  neck  (i)  the  superior  laryngeal  nerve  to  the  larynx  ;  (2)  the  cervical 
cardiac  branches  ;  (3)  the  pharyngeal  branches  ;  (4)  the  recurrent  laryngeal 
nerve. 

For  the  present  remember  this  :  The  pneumogastric  supplies  the  organs  of 
voice  and  respiration  with  motion  and  sensation  ;  the  organs  of  circulation  and 
digestion  with  motion  only. 

The  internal  carotid  artery  on  each  side  begins  at  the  bifurcation  of  the 
common  carotid.  Find  this  bifurcation  and  see  whether  it  is  opposite  the  thyroid 
cartilage  or  the  hyoid  bone.  The  internal  carotid  has  four  stages  : 

i.   The  ccrrical — to  the  base  of  the  skull,  from  the  bifurcation. 


Fiu.   31. — VESSELS  ANIJ  NERVES  OF  THE  HEAD  AND  NECK. 

I.  Subclavian  artery.  2.  Subclavian  vein.  3,  3.  Common  carotid  artery.  4.  internal  jugular  vein. 
5.  Anterior  jugular  vein.  6.  Omo-hyoid  muscle.  7.  Sterno-hyoid  muscle.  8.  Trunk  of  pneumo- 
gastric nerve.  9.  Hypo-glossal  nerve.  10.  Its  terminal  portion.  if.  Its  descending  branch. 
12.  Internal  descending  branch  of  cervical  plexus.  13.  Plexus  formed  by  last  two  branches. 
14.  External  carotid  artery.  15.  Superior  thyroid  artery  and  vein.  16.  Lingual  and  facial  arteries. 
17.  Facial  artery  and  vein.  18.  Occipital  artery.  19.  Anterior  branches  of  the  first  four  cervical 
nerves.  20.  Superior  laryngeal  nerve. 

2.  The  petrosal — in  the  carotid  canal  in  the  petrosa. 

3.  The  cavernous — in  the  cavernous  sinus  on  the  lingula. 

4.  The  cci'cbral — at  the  base  of  the  brain  in  the  cranium. 

The  cervical  stage  gives  off  no  branches  in  the  neck.  The  function  of  this 
artery  is  to  take  blood  to  the  brain,  eye,  and  nose.  It  assists  the  vertebral  in 
forming  the  circle  of  Willis,  by  which  circle  the  brain  receives  all  its  blood. 
Blood  returns  from  the  brain  by  the  internal  jugular  vein. 

External  Carotid  Artery. — This  vessel  begins  at  the  bifurcation  of  the 
common  carotid  artery  just  mentioned.  In  some  tubercular  cases  you  will  find 


6o 


PRACTICAL  ANATOMY. 


a  large  nest  of  enlarged  glands  here  at  the  bifurcation.     The  following  are  the 
branches  of  the  external  carotid  artery  and  their  attendants  : 

1.  The  superior  thyroid  artery,  vein,  nerve,  lymphatic. 

2.  The  lingual  artery,  vein,  nerve,  lymphatic. 

3.  "£\\e  facial  artery ,  vein,  nerve,  lymphatic. 

4.  The  occipital  artery,  vein,  nerve,  lymphatic. 

5.  The  posterior  auricular  artery,  vein,  nerve,  lymphatic. 

6.  The  ascending  pharyngeal  artery,  vein,  nerve,  lymphatic. 

7.  The  temporal  artery,  vein,  nerve,  lymphatic. 

8.  The  internal  maxillary  artery,  vein,  nerve,  lymphatic. 

NOTE. — It  has  been  pointed  out  in  a  foregoing  paragraph  that  sympathetic 
nerves  accompany  every  branch  of  the  external  carotid  artery.  Morris  shows 
that  the  deep  lymphatics  of  the  head  and  neck  roughly  follow  the  course  ot 
the  deep  arteries,  and  finally  terminate  in  the  glandular  concatenatae  previously 
described.  Hence  in  vour  dissection  of  the  branches  of  the  external  carotid, 


Falato-gloasus 


Descending  palatine  arteri, 
Palato-pharyngeus 

TONSIL 

Ascending  palatine  branch 

of  facial 
Tonsillar  branch  of  dorsalis 

linguae 

Tonsillar  branch  of  facial 
Stylo-glossuB   - 

Dorsalis  lingua  artery 

Middle  constrictor 
HYPOGLOSSAL  NERVE 

Facial  artery 

Posterior  belly  of  digastric 
and  stylo-hyoid 
Supra-hyoid  branch 

SUP.  LARYNGEAL  K. 

Infra-hyoid  branch 

Internal  carotid  artery 


Ronnie  artery 


Q-enio-hyoid 
Anterior  belly 
of  digastric 


ur /rry 
Superior  thyroid  artery 


External  carotid  artery 
Common  carotid  arlrry 

FlG.    32.  —  SCH  KM  K    OK    TI1K    LlNCJUAI.    ARTKRY. 


,,: 


you  will  remember  you  can  always  find  the  vein  corresponding  to  the  artc 
the  sympathetics  may  be  found  by  treating  the  artery  with  ether  and  formaline  ; 
the  lymphatic  glands  can  only  be  demonstrated  when  enlarged  by  disease.  As  t<> 
the  lymphatic,  I  would  urgently  request  the  student  to  study  carefully  t 
schematic  drawings  of  these  vessels  by  Professor  F.  R.  Sherwood,  in  Mor 
"  Anatomy." 

Caution. — Never  use  a  cutting  instrument  in  dissecting  arteries.     The  fore 
or  dissecting  hook  is  all  you  need  to  divide  the  connective  tissue.      Handle  veins 
with  gentle  touch  ;  they  are  very  easily  ruptured. 

Specific  ] Dissection. — The  lingual  artery:  (i)  find  this  vessel  above  the 
greater  horn  of  the  hyoid  bone  ;  (2)  a  little  below,  and  running  parallel  with,  the 
hypoglossal  nerve  ;  (3)  passing  behind  the  free  margin  of  the  hyo-glossus  muscle 
to  the  tongue.  (Fig.  32.) 

The  Superior  Thyroid  Artery. — (i)  It  is  the  first  branch  given  off  by  the 
external  carotid  ;  (2)  it  goes  to  the  upper  part  of  the  thyroid  gland  ;  (3)  it  gives 
off  the  superior  laryngeal  branch,  which  always  accompanies  the  superior  laryn- 


THE    HI:,  in   AND   XECK. 


61 


geal  nerve  ;  (4)  these  structures,  the  superior  laryngeal  nerve  and  artery,  pierce 
the  thyro-hyoid  membrane  ;  (5)  the  anastomosis  is  feeble  with  the  opposite  side  ; 
free  with  the  inferior  laryngeal  artery,  and  the  distribution  is  to  the  gland  and  to 
the  depressor  muscles  of  the  hyoid  bone  that  cover  the  gland.  (Fig.  28.) 

The  facial  artery:  (i)  often  given  off  with  the  lingual;  (2)  note  its  deep 
course  behind  the  hypoglossal  nerve,  the  stylo-hyoid  muscle,  the  digastric 
muscle,  the  parotid  gland.  It  crosses  the  mandible  in  front  of  the  masseter 
muscle.  Its  specific  sympathetic  nerves  are  called  nervi  molles.  (Fig.  17.) 

The  facial  vein  (Fig.  18),  you  will  note,  takes  a  superficial  course.     It  lies  in 


Anterior  branch  of  pos- 
terior auricular 

I'osterior  branch  of  pos- 
terior auricular 


PAROTID  GLAND- L_, 

Sterno-mastoid,  cut 

Auricular  branch  of 
occipital 

Rectus  capitis  lateralia 

Sl'IXAL  ACCESSORY 

NER  VE 
Posterior  auricular 

Internal  jttfjit/itr  n'in 
Facial  artery 

J/Y/'OflLOSXAL  y. 

J.int/iirtl  nrferi/ 

PNEUMOOASTRIC 


rio/'  Itiiiroi'l 


Common  carotid 


External  branch  of 
occipital 


Internal  branch  of 
occipital 

ComplexuB 

Priceps  cervicis 

—  Superior  oblique 
Trachelo-mastoid,  cut 
Splenius  capitis,  cut 
Meningeal  brancln'x 

Sterno-mastoid  branch  oj 
occipital 

Internal  carotid 

—  Sterno-mastoid 

—  External  carotid 
—   Trapeziua 


FIG.  33.— SCHEME  OF  OCCIPITAL  AND  POSTERIOR  AURICULAR  ARTERIES. 

front  of  the  structures  behind  which  the  facial  artery  passes.      It  opens  into   the 
external  jugular  vein.      In  your  dissection  show  all  the  structures  by  which  the 
facial  artery  and  vein  are  separated  in  their  cervical  stage. 
Branches  of  the  facial  artery  in  the  neck  are  : 

1.  To  the  stylo-hyoid,  internal  pterygoid,  masseter,  and  buccinator. 

2.  Submaxillary  branches  four,  to  the  submaxillary  gland. 

3.  Submental  artery  to  structures  under  the  chin. 

4.  Tonsillar  branches  to  the  tonsil  and  tongue. 

5.  Ascending  palatine  branches  to  the  soft  palate. 

The  Occipital  Artery  (Fig.  33). — (i)  Find  the  hypoglossal   nerve  passing 


62 


/'A' A  CTICAL  ANA  TOM ) '. 


under  and  behind  and  external  to  it,  to  gain  its  place  in  front  of  the  internal  and 
external  carotids  ;  (2)  it  passes  behind  the  digastric,  sterno-mastoid,  splenius 
capitis  ;  (3)  it  gives  off  the  arteria  princeps  cervicis,  which  anastomoses  with  the 


Stylo-, 

INFERIOR  DENTAL  NERVE 
CHORDA   TYMPANI   I         / 
FACIAL  NERVE  j     /       / 
Internal  maxillary  artery 
Stylo-hyoid,  turned  up 
Digastricus,  turned  up 
Temporal  artery 


glossus 

S'lliinental  artery 
I  Facial  artery 

MYLO-HYOID  NERVE 

LOWER  JAW,  TURNED  UP 


Posterior  auricular  artern 
Internal  jugular  rein    \ 


SECOND  CERVICAL 

NERVE 

SPINAL  ACCESSORY 
NERVE 

Eectus  capitis  auticua  major 
Stylo-pharyngeus  muscle 
SUP.  CER.  GANGL.  OF  SYMPATHETIC 
GLOSSO-PHAR.  NERVE 
Sterno-mastoid,  reflected 
Occipital  artery 
Internal  carotid 
Levator  anguli  scapulae 
THIRD  CERVIC.  NERVE 
DESCENDED  HYPO- 
GLOSS  I  NER  VE 

External  carotid 
Inferior  constrictor 

COMMl'N.  HYPOGLOSS1 

FOURTH  CERV.  NERVE 

Ascending  cervical  artery 

SPINAL  ACCESSORY  f 

PHRENIC  NER  VE 

Scalenus  anticus 

Levator  anguli  scapula: 

FIFTH  CERV.  NER  VE 
Scalenus  medius 
CERVICAL  I' LEX  US 
DESCJSNDENS  BRA  NCH 
PNEVMOGA3TRIC  / 

NER  VE 

BRACHI.iL  PLEXUS 

(SIXTH  CERVICAL) 

Internal  ja/jnlar  rein 

Superficial  ceii'ical  artery 

Suprasca pnlar  artery 

Serratus  magnus 


Coraco-brachialis    t  \ 


Suprascapular  artery  given  uff  front  ttiiril 
part  nf  snbclai  inn 

Posterior  scapular  artery 
SUPRASCA  PULA  R  NER  VE 

Humeral  thoracic  artery 


SUB  MA  XI L  LA  R  Y  GA  NGL10N 
G  USTA  TOR  Y  NER  VE 

SUBMAXILLARY   DUCT 
SUBMAXILLARY  GLAND 
TONGUE 

HYPOGLOS.  NERVE 
Rmiiite  artery 

Qenio-hyo-glossus 
Sublinyual  arteiy 

Lingual  artery 
Artery  affrcenitm 

LOWER  JAW 

Genio-hyoid 

Hyo-glossus 
Liniinal  artery 
Ifyoid  branch 
Mylo-hyoid  muscle 
Thyro-hyoid  membrane 
SUPERIOR  LARYN- 

GEAL  NERVE 
Superior  laryiigeal  artery 
Thyro-hyoid 
Superior  l/ii/njii!  artery 
Omo-hyoid 
EX  TERN  A  L   LA  R  YN- 

GEAL   NERVE 
THYROID  GLAND 


Sterno-hyoid 
Coiiiiiitin  carotid 
Sterno-thyroid 
Vertilnal  artery 
Inferior  thyroid  artery 
. I nterinr  j nyiilar  vein 


CLAVICLE 
Verttbral  rein 

KRACIIIAL  PLEXl 

(SEVENTH  CERVIC.) 

Siilic/nrinii  artery 

Pectoralia  major, 
reflected 


V     Transverse  cervical  artery 
Subclavius,  reflected 

BRACIIIAL  I'LEXfS  (EIGHTH  CERVK'M.) 
Pectoral  branch  of  acromial  thoracic  arteiy 


Posterior  belly  of  omo-hyoid,  drawn  down 

Pectoral  a  minor 


Fic.   34.— THE  COMMON  CAROTID,  TIIK  EXTKRNAI.  AND   I.MKKNAI.  CAROTID,  AND  mi.  Sruci  \\i 

AKIKRIKS  OK  TIIK  RICHT  SIDE  AND  THEIR  BRANCHES. 
(From  a  dissection  by  Dr.  Alder  Smith  in  the  Museum  of  St.  Bartholomew's  Hospital.) 


deep  cervical,  a  branch  of  the  superior  intercostal,  and  the  vertebral  artery. 
This  anastomosis  keeps  up  the  collateral  circulation,  after  ligation  of  the  common 
carotid  artery. 


'/'//A'    HI 'I.  ID  AND  NECK.  63 

The  posterior  auricular  artery  arises  high.  You  will  find  it  behind  the 
parotid  gland.  Trace  it  very  close  to  the  ear  ;  between  the  ear  and  the  mastoid 
process  of  the  temporal  bone. 

The  superficial  temporal  arteries  are  in  the  superficial  fascia  covering  the 
temporal  muscle.  They  are  attended  by  the  sensory  auriculo-temporal  branches 
of  the  fifth  cranial  nerve.  Note  the  deep  temporal  vein  piercing  the  temporal 
fascia  above  the  zygoma.  (Fig.  18.) 

The  ascending  pharyngeal  you  will  find  buried  in  connective  tissue,  lying 
between  the  internal  and  external  carotid  arteries.  It  arises  from  the  external 
carotid  near  the  bifurcation.  It  is  the  smallest  branch  of  the  external  carotid. 
It  is  distributed  to  the  pharynx  and  meninges. 

The  internal  maxillary  will  be  dissected  with  the  muscles  of  mastication 
and  the  fifth  cranial  nerve.  (Fig.  51.) 

The  Hypoglossal  Nerve  (Fig.  31). — Find  this  nerve  crossing  the  internal 
and  external  carotid  arteries  a  little  above  the  bifurcation  of  the  common  carotid 
artery.  Note  that  this  nerve  lies  a  little  distance  above  the  lingual  artery  ;  that 
the  artery  crosses  behind  the  hyo-glossus  muscle,  the  nerve  in  front  of  the 
muscle.  The  nerve  gives  off  the  following  branches  : 

1.  To  the  thyro-hyoid  muscle. 

2.  To  the  stylo-glossus  muscle. 

3.  To  the  hyo-glossus  muscle. 

4.  To  the  genio-hyoid  muscle. 

5.  To  the  genio-hyo-glossus   muscle. 

6.  To  the  sterno-hyoid  muscle. 

7.  To  the  omo-hyoid  muscle. 

8.  To  the  sterno-thyroid  muscle. 

9.  To  the  meninges  ;  recurrent  branches. 

All  these  branches,  except  the  meningeals,  you  can  readily  trace  out.  This 
nerve  must  not  be  mistaken  for  the  superior  laryngeal  branch  of  the  pneumo- 
gastric.  Now  compare  the  two  nerves  in  their  relation  to  the  carotid  arteries  on 
your  dissection.  The  result  of  section  of  this  nerve  will  be  considered  when 
you  dissect  the  tongue  and  outline  its  complete  nerve-supply. 

Dissect  the  following  muscles  (Fig.  35) : 

1.  The  digastric  and  its  intermediary  tendon. 

2.  The  stylo-hyoid  muscle. 

3.  The  mylo-hyoid  muscle. 

4.  The  hyo-glossus  muscle. 

I.  Find  the  insertion  of  the  stylo-hyoid  muscle  into  the  lower  border  of  the 
body  of  the  hyoid  bone  at  the  junction  of  the  greater  cornu  and  body  of  the 
hyoid  bone.  Study  the  relation  of  the  intermediary  tendon  of  the  digastric  to 
the  aponeurosis  of  the  stylo-hyoid  muscle.  Trace  the  origin  of  the  stylo-hyoid 
muscle  to  the  base  and  outer  surface  of  the  styloid  process  of  the  temporal  bone. 

The  Digastric  has  an  anterior  belly,  that  lies  on  the  mylo-hyoid  muscle,  a 
posterior  belly,  that  lies  under  the  stylo-hyoid  muscle  just  found,  an  intermediary 
tendon,  and  a  suprahyoid  aponeurosis.  Carefully  detach  the  anterior  belly  of 
the  digastric  muscle  from  the  digastric  fossa  of  the  mandible,  and  as  you  pull 
this  detached  belly  down,  divide  the  connective  tissue  between  this  and  the  mylo- 
hyoid  muscle.  Notice  the  nerve-supply  to  the  anterior  belly  of  the  digastric — 
the  mylo-hyoid  branch  of  the  inferior  dental.  The  mylo-hyoid  muscle  is  now 
in  full  view  since  you  removed  the  anterior  belly  of  the  digastric  muscle.  It 
forms  the  floor  of  the  mouth.  It  arises  from  the  internal  oblique  line  or  mylo- 
hyoid  ridge  on  the  inner  surface  of  the  body  of  the  inferior  maxilla.  It  is  in- 
serted into  the  mid-line  of  the  neck  into  its  fellow  of  the  opposite  side.  This 
muscle  will  be  studied  when  you  dissect  the  mouth  and  tongue. 


64 


PR  A  CTICA  L  ANA  TO.  U ) . 


The  Hyo-glossus  Muscle  (Pig.  32). — This  is  the  muscle  that  separates 
the  hypoglossal  nerve  from  the  lingual  artery.  It  arises  from  the  body  and 
greater  and  lesser  cornua  of  the  hyoid  bone.  It  passes  to  the  tongue.  It  is  the 
most  deeply  located  muscle  in  this  region. 

The  great  branches  from  the  transverse  part  of  the  arch  of  the  aorta  may  be 
reviewed.  In  fact,  you  can  not  study  them  and  their  relations  too  much.  The 
innominate  has  been  seen  dividing  into  the  right  subclavian  and  right  common 
carotid.  You  may  now  dissect  the  branches  of  the  subclavian  artery  and  vein. 

The  Subclavian  Artery  and  Vein. — The  subclavian  artery  has  three  stages  : 

1.  From  its  beginning  to  the  inner  border  of  the  scalenus  anticus. 

2.  The  artery  behind  the  scalenus  anticus.      (Fig.  36.) 

3.  From  the  scalenus  anticus  to  the  lower  border  of  first  rib. 


Stylo-glossus 

Hyo-glossus 

Mylo-hyoid 

Anterior  belly  _ 
of  digastric 

Raplie  of  mylo-  - 
byoid 

Thyro-hyoid 
Inferior  constrictor 

Anterior  belly  of 
omo-hyoid 

Sterno-hyoid 


Sterno-thyroid     - 


—  Scalenus  posticus 


mft      Posterior  belly  of 
omo-hyoid 


I.'K;.  3$. — ANTKRIOR  ANI>  LATKKAI.  CKKVICAJ.  Mus<  i  i -. 

Find  the  scalenus  anticus  muscle  inserted  into  the  scalene  tubercle  of  the  first 
rib.  In  a  groove  in  front  of  this  tubercle  find  the  ntbclavian  vein  ;  behind  the 
tubercle  find  the  subclavian  artery.  Behind  the  artery  find  the  scalcnns  incdius 
muscle  inserted  into  the  first  rib.  Above  the  artery  observe  the  anterior  primary 
divisions  of  the  fifth,  sixth,  seventh,  and  eighth  cervical  nerves  and  first  dorsal 
nerve  between  the  scalenus  anticus  and  scalenus  medius  forming  the  brachial 
plexus, 

The  subclavian  arteries  differ  on  the  two  sides  ;  the  stages  and  branches,  how- 
ever, are  the  same  in  each  as  to  name.  The  first  stage  of  the  left  subclavian  is 
longer  than  the  first  stage  of  the  right. 

The  right  subclavian  artery  begins  behind  the  right  sterno-clavicular  articula- 
tion, at  the  bifurcation  of  the  innominate  artery.  The  artery  lies  very  deeply.  In 


THE  HEAD  AND  NECK.  65 

front  of  it  are  the  skin,  superficial  fascia  containing  the  platysma  myoides,  the 
clavicular  head  of  the  sterno-cleido-mastoid  muscle,  the  sterno-hyoid  and  sterno- 
thyroid  muscles.  The  phrenic  nerve,  the  cardiac  branches  of  the  sympathetic 
nerve,  the  vagus  nerve,  the  vertebral  and  internal  jugular  veins,  cross  this  artery. 
Behind  the  artery  is  the  neck  of  the  first  rib  and  the  longus  colli  muscle  and  the 
recurrent  laryngeal  nerve  ;  below  the  artery  is  the  pleura,  against  wounding  which 
the  greatest  precautions  should  be  taken  in  operations  in  this  locality. 

The  left  subclavian  artery  is  longer  than  the  right ;  it  does  not  arch  outward 
like  the  artery  of  the  opposite  side,  but  ascends  vertically  to  the  inner  border  of 
the  scalenus  anticus  muscle  and  is  situated  more  deeply  in  the  thorax.  In  front 


PostSfu.ntii 
AnlSfunai 


FIG.  36. SCHEME  FOR  HEAD  AND  UPPER  EXTREMITY. 

of  the  artery  are  the  lung  and  pleura,  the  vagus,  phrenic,  and  cardiac  nerves,  the 
left  common  carotid  artery,  internal  jugular  and  vertebral  veins,  and  left  brachio- 
cephalic  vein,  the  sterno-hyoid,  sterno-thyroid,  and  sterno-cleido-mastoid  mus- 
cles Behind  the  artery  are  the  oesophagus,  thoracic  duct,  inferior  cervical  gang- 
lion, longus  colli  muscle,  anH  vertebral  column.  To  the  outer  side  of  the  artery 
is  the  pleura ;  to  the  inner  side  are  the  trachea,  thoracic  duct,  and  oesophagus. 

Branches  of  the  subclavian  artery : 

The  internal  mammary  to  anterior  thoracic  and  abdominal  walls. 

The  vertebral  to  the  brain  and  spinal  cord  and  vertebrae. 

The  superior  intercostal  to  the  first  and  second  intercostal  spaces. 


66 


PR  A  CTICAL    ANA  TO.  M ) . 


The  suprascatpular  to  the  shoulder. 

The  inferior  tliyroid  to  the  thyroid  gland. 

The  transvcrsalis  colli. 

1.  The  internal  mammary  (Fig.  36)  is  given  off  from  the  under  part  of 
the  first  stage  of  the  subclavian  artery.      Its  course,  branches,  anastomoses,  and 
important  relations   are  in   the  anterior  thoracic  walls,  where   you   will   find  its 
description  when  you  dissect  that  part. 

2.  The  suprascapular  artery  (Fig.  37)  is  attended  by  a  vein  and  nerve  of 
the  same  name.      It  crosses  the  trunks  of  the  brachial  plexus,  and  is  distributed 
to  the  supra-  and  infraspinati  muscles. 

3.  The  Inferior  Thyroid  Artery. — Trace   this  artery  behind  the  common 
carotid  artery  and   sympathetic  nerve.     Very  often  the  middle  cervical  ganglion 
of  the  sympathetic  nerve  rests  on  the  inferior  thyroid  artery.      Usually  the  artery 


Scalenus  medius 

Scale-ius  anticua  and 

on  it  phrenic  nerve 

Transverse  CITI  ifal 
artery 


Suprascn/inlnr  nrtf.ry 


Sitbcliiiian  artery 

conn  OF  BRA  CIHA  L 

f'LK.YUX,    GIVING 
OFF  MUSCULO- 
CUTAXEOUS    ANT) 
OUTER    HEAD  OF 
MEDIAN  NERVES 


Axillary  artery 


IfUSCULO-SPIRA  L 

NKR  \'E 


T/ii/roitl  mix 
Internal  j ugii/ar  vein 


Right  common  carotid 

artery 

PNEUMOGA8TR1C 
NERVE 

ieiK-fnirnt  of 
iniiominatf,  vein 


FIG.  37. — THE  SUBCLAVIAN  VKSSKI.S. 
(From  a  dissection  in  the  Hunterian  Museum.) 


lies  in  front  of  the  recurrent  laryngeal  nerve  ;  sometimes  you  will  find  the  reverse 
is  true.  In  operations  on  the  thyroid  gland  isolate  (i)  the  recurrent  laryngeal 
nerve,  (2)  the  sympathetic. 

The  branches  of  the  inferior  thyroid  artery : 

1.  The  inferior  laryngcal  to  the  larynx. 

2.  Trachcal  branches  to  the  trachea. 

3.  Utsopltagcal  branches  to  the  oesophagus. 

4.  Jtram/ies  to  the  depressor  muscles  of  the  hyoid  bone. 

5.  Ascending  cervical  brandies  to  the  muscles  of  the  neck. 

The  Superior  Intercostal  Artery  (Fig.  39). — This  is  given  off  from  th< 
second  stage  of  the  subclavian  artery.  It  gives  off  a  communicating  branch  t( 
the  first  aortic  intercostal,  which  you  will  find  high  in  the  thorax,  when  yoi 


THE  HEAD  AND   NECK.  67 

remove  the  pleura.  The  artery  gives  off  its  deep  cervical  branch,  which  inos- 
culates with  the  arteria  princcps  cervicis,  a  branch  of  the  occipital.  The  anasto- 
mosis takes  place  between  the  complexus  and  semispinalis  colli  muscles.  By 


Right  anterior  cerebral 

Internal  carotid 
Right  posterior  cerebral 


Occipital 
Princeps  cervicis 

External  carotid 

Superficial  branch  of  princeps  cervicis 
Deep  branch 

Ascending  cervical 


Transverse  cerrinil 
Posterior  scapular 
Acromial  branch 
Subscapular  brunch ,- 

Supraspinous ^ 

branch 

Anterior  circumflex 
Infraspimrtii 

branch 

Posterior  circumflex 

Long  thoracic 

Subicapulai 

Dorsal  scapular 
fnfraieapttlar 

Subscapular 


Left  anterior  cerebral 
—    Anterior  cotlMnunicutilig 


Posterior  comma  n icatiny 
Left  posterior  cerebral 

Basilar 


Anterior  spinal 


Superior  thyroid 


Inferinr  (lit/mid 

Common  carotid 


Thyroid  axis 
Superior  inten-ostai 


Illin>ltliliat<! 

'<>!•   intrrriis'iil 
I.H't  ennnnon   carotid 
LfJ't  subclavinn 
—  tjhiirt  thoracic 

lii/ernal  mammary 


Anterior  intercostal 

I-'irxt  aortic  inter- 
costal 

Second  aor/ic  inter- 
comtal 


A n lerior  in tcrcosla  I 


Third  aortic  inter- 
costal 


FIG.  38. — THE  COLLATERAL  CIRCULATION  AFTER  LIGATURE  OF  THE  COMMON  CAROTID  AND 

Si  ix  I.AVIAN  ARTERIES. 
(A  ligature  is  placed  on  the  common  carotid  and  on  the  third  portion  of  the  subclavian  artery.) 


this    anastomosis   the   collateral  circulation   is   carried   on  after  ligature  of  the 
common  carotid  artery.      (Figs.  38,  39,  and  40.) 

The  vertebral   artery  (Fig.  40)  is  given  off  from   the   second  stage  of  the 


68 


PRACTICAL  ANATOMY. 


subclavian.  It  passes  through  the  foramina  in  the  transverse  processes  of  the 
cervical  vertebrae,  except  the  lower  two,  and  through  the  foramen  magnum,  in 
the  occipital  bone,  to  assist  the  internal  carotid  artery  in  forming,  by  anasto- 
mosis, the  circle  of  Willis.  The  artery  is  attended  by  a  sympathetic  plexus  of 
nerves  from  the  inferior  cervical  ganglion.  The  artery  is  found  lying  in  the 
vertebral  groove,  at  the  junction  of  the  lateral  mass  and  posterior  arch  of  the 
atlas  in  the  suboccipital  triangle,  at  the  base  of  the  skull.  This  triangle  is 
bounded  by  the  superior  and  inferior  oblique  and  rectus  capitis  posticus  major 
muscles.  The  roof  of  the  triangle  is  the  complexus  muscle. 
Branches  of  the  vertebral  artery  are  as  follows  : 

1.  Muscular  branches  to  the  deep  muscles  of  the  neck. 

2.  Lateral  spinal  arteries  to  the  spinal  cord  and  meninges  ;  the  bodies  of  the 
vertebrae  also  receive  blood  from  these  branches. 


Scalenus  anticus  muscle 

Deep  cervical  branch 

FIRST  DORSAL  NERVE 


FIRST  INTERCOSTAL 
NER  VE 

Subclavian  artery 


SECONH  I  \TKRCOSTAL 


Anterior  intercostal 

artery 

THIRD  INTER- 
COSTAL NERVE 


Anterior  intercostal 
artery 


Intercostal  vessels  qf 
third  space 


SYMPA  THE  TIC 
SER  VE 


INFERIOR  CERVI- 
CAL GANGLION 

}  Superior  intercostal 
artery 


Arter ia  aberrant 


Branch  from  first  aortic 
intercostal 


Arteria  aberrant 


Fint  aortic  intercostal 

artery 


Second  aortic  intercostal 
artery 


Intei  costal  vessels  of  fourth  space 

FIG.  39. — SCHEME  OF  THE  SUPERIOR  INTERCOSTAL  ARTERY. 


3.  Anterior  and  posterior  spinal  branches  that  may  be  well  seen  when  y( 
dissect  the  cord. 

4.  Posterior  inferior  ccrcbellar  arteries.      These  are  the  largest  arteries  given  off 
from  the  vertebral.     They  will  be  studied  when  we  consider  the  structures  seen 
on  removing  the  brain.     The  two  vertebral  arteries  unite,  within  the  cranium,  to 
form  the  basilar  artery.     This  artery  will   be   studied  when    you  remove  the 
brain. 

The  transversalis  colli  is  a  branch  of  the  thyroid  axis.  It  gives  off  the 
posterior  scapular  artery,  by  which  collateral  circulation  is  established  with  the 
subscapular  branch  of  the  axillary  artery  in  cases  of  ligation  of  the  third  stage 
of  the  subclavian  artery.  (Figs.  38,  39,  and  40.) 

The  scaleni  muscles  are  three  in  number.  You  have  already  studied  their 
insertion  into  the  first  and  second  ribs.  You  will  now  review  the  relation  be- 


THE  HEAD  AND  NECK. 


69 


tween  the  subclavian  vein  and  artery  on  the  outer  surface  of  the  first  rib.  You 
will  again  see  the  nerves  that  are  to  form  the  brachial  plexus  coming  through 
between  the  scalenus  anticus  and  scalenus  medius  muscles  above  the  subclavian 
artery.  You  will  find  the  phrenic  nerve  lying  on  the  anterior  surface  of  the 
scalenus  anticus  muscle.  You  will  in  time  trace  it  between  the  subclavian  vein 
and  artery  into  the  thorax,  down  in  front  of  the  root  of  the  lung,  to  the  diaphragm, 
and  all  the  serous  membranes  continging  the  diaphragm,  for  distribution. 

Origin  of  the  Scaleni  Muscles. — To  aid  the  memory,  remember  the  num- 
erals 3,  6,  3.  The  scalenus  anticus  arises  from  the  anterior  tubercles  of  the  lower 
three  transverse  processes  ;  the  scalenus  medius  from  the  lower  six ;  the  scale- 
nus posticus  from  the  lower  three.  The  last  two  arise  from  posterior  tubercles. 
Remember,  scarcely  any  two  dissections  will  show  exactly  the  same  origin  ; 


I!i</ht  posterior  cerebral  artery 

Left  posterior  cerebral  artery 

Basilar  artery 

BASILAR  PROCESS,  OCCIPITAL  BONE 

Intracranial  portion  of  vertebral  artery 
Reetus  capitis  lateralis  muscle 

FIRST  CER  VIC  A  L  NER  VE 

Commencement  of  vertebral  vein 

SECOND  CERVICAL  NERVE 

Vertebral  plexus  of  reins 

THIRD  CERVICAL  NERVE 

Vertebral  portion  of  vertebral  artery 
FOURTH  CERVICAL  NERVE 

Vertebral  plexus  of  veins 
FIFTH  CERVICAL  NERVE 

SIXTH  CERVICAL  NERVE 

Inferior  thyroid  artery 

Longus  colli  muBde 

Cervical  portion  of  vertebral  artery 

Internal  jugular  vein,  hooked  a  little 
aside 

Vertebral  vein,  cut 
Subclavian  artery 


Right  and  left  svpe- 

*• rior  cerebellur 

arteries 

OCCIPITAL  BONE 


Bectus  capUis  pos- 
ticus minor  mus- 
cle 


Occipital  portion  of  vertebral  artery 


Arleria  princejm  cerrlcis 


Semispiualis  colli  muscle 

Deep  cervical  artery 

Scalenus  anticus  muscle,  cut 
Thyroid  axis,  hooked  a  little  aside 
Subclarian  vein 


FIG.    40. SCI!  KM  K    OK    THK    YKRTKUKA1,    ARTKRY. 

The  internal  jugular  and  vertebral  veins  are  hooked  aside  to  expose  the  artery. 

hence  it  is,  scarcely  any  two  authors  will  give  the  origin  of  these  muscles  alike. 
The  foregoing  is  a  general  average  and  easily  remembered — 3,  6,  3. 

The  Levator  Anguli  Scapulae  Muscle. — It  is  necessary  to  have  exact 
knowledge  of  this  muscle,  to  understand  your  dissection  of  the  plexuses.  This 
muscle  arises  from  the  posterior  tubercles  of  the  transverse  processes  of  the 
upper  three.  You  will  find  the  tendons  of  origin  of  this  muscle  becoming  fleshy. 
They  will  unite  to  form  a  flat  muscle,  two  inches  broad.  This  muscle  will  be 
inserted  into  the  middle  lip  of  the  vertebral  border  of  the  scapula,  from  the 
superior  angle  to  the  vertebral  end  of  the  scapular  spine.  Find  its  nerve-supply 
coming  from  the  cervical  plexus. 


70  PRACTICAL    ANATOMY. 

1.  Locate  tlie  thyroid  gland. 

It  is  in  the  third  layer  of  deep  cervical  fascia.  It  embraces  the  cricoid  car- 
tilage of  the  larynx  and  the  upper  part  of  the  trachea. 

2.  From  illicit  source  docs  the  tJiyroid  gland  receive  its  blood  / 

From  the  superior  thyroid  artery,  a  branch  of  the  external  carotid,  and  from 
the  inferior  thyroid,  a  branch  of  the  thyroid  axis  of  the  subclavian  artery. 

3.  Does  anastomosis  occur  between  tlie  right  and  left  thvroid  arteries  / 
Yes  ;  this  occurs,  but  very  scantily,  in  the  isthmus. 

4.  Does  the  thyroid  ever  receive  blood  from  any  other  source  / 

Yes  ;  it  may  receive  an  artery  either  from  the  arch  of  the  aorta  or  from  the 
innominate  artery,  called  the  thyroidea  ima. 

5.  From  what  source  does  the  thyroid  gland  derive  its  nerve-stepply  ? 
From  the  middle  cervical  ganglion  of  the  sympathetic. 

6.  By  ivhat  structures  is  the  thyroid  gland  covered  ? 

By  the  skin,  superficial  fascia,  first  and  second  layers  of  deep  fascia,  the  latter 
containing  the  depressor  muscles  of  the  hyoid  bone. 

7.  Give  contents  of  the  carotid  sheath  and  locate  the  same. 

It  contains  the  common  carotid  artery,  the  pneumogastric  or  vagus  nerve,  and 
the  internal  jugular  vein.  On  the  sheath  lies  the  ansa-hypoglossal  loop,  from 
which  the  depressor  muscles  of  the  hyoid  bone  are  innervated.  The  sheath  is 
in  the  third  layer  of  deep  cervical  fascia,  and  crossed  near  its  middle  third  by  the 
omo-hyoid  muscle. 

8.  Explain  the  common  carotid  artery. 

It  lies  to  the  inner  side  of  the  sheath,  very  near  the  larynx  and  trachea.  To 
its  outer  side  is  the  internal  jugular  vein.  It  is  crossed  by  the  ansa-hypoglossal 
loop  and  omo-hyoid  muscle.  On  the  right  side  it  begins  at  the  bifurcation  of  the 
innominate  artery,  behind  the  sterno-clavicular  joint ;  on  the  left  side  it  begins 
at  the  arch  of  the  aorta.  The  common  carotid  arteries  end  near  the  hyoid  bone 
by  dividing  into  the  external  and  internal  carotids,  having  given  off  no  branches 
in  their  course. 

9.  Describe  the  internal  carotid  artery. 

It  begins  at  the  bifurcation  of  the   common   carotid,  and  has  four  stages  : 

(1)  The  cervical  stage  to  the  base  of  the  skull,  where  it  enters  the  temporal  bone  ; 

(2)  the  petrosal  stage,  where  it  passes  through  the  carotid  canal  in  the  petrosal 
part  of  the  temporal  bone  ;     (3)  the  cavernous  stage,  where  it  lies  in  the  caver- 
nous sinus  of  the  dura  mater,  by  the   side  of  the   body  of  the  sphenoid  bone  ; 
(4)  the  cerebral  stage,  where  it  comes  through  the  dura  mater  to  give  off  its 
terminal  branches  to  the  brain. 

10.  Name  the  branches  given  off  from  tJie  intracranial  portion  of  tJie  internal 
carotid. 

(i)  It  contributes  the  anterior  cerebral,  the  middle  cerebral,  and  the  posterior 
communicating  to  the  circle  of  Willis.  (2)  It  gives  off  the  ophthalmic  artery 
for  the  supply  of  the  orbit  and  its  contents,  the  ethmoidal  cells  and  the  inner  and 
outer  nose  in  part.  (3)  It  gives  off  the  anterior  meningeal  arteries  to  the  dura 
of  the  anterior  fossa  of  the  base  of  the  skull.  (4)  It  supplies  the  Gasserian 
ganglion. 

1 1.  \Vliat  brandies  are  given  off  from  the  petrosal  stage  ? 

(i)  The  Vidian,  which  is  said  to  anastomose  with  the  Vidian  branch  of  the 
internal  maxillary.  (2)  The  tympanic,  which  goes  to  the  middle  ear  and  anas- 
tomoses with  the  tympanic  branches  of  the  internal  maxillary  and  stylo-mastoid 
arteries. 

12.  Name  all  the  structures  between  the  sh'/i   and  the  internal  carotid  one-half 
of  an  incJi  below  flic  base  of  tlie  skull. 

(i)  The  parotid  gland  ;  (2)  posterior  belly  of  the  digastric  muscle  ;  (3)  stylo- 


THE  HEAD  AND  NECK.  7, 

hyoid  muscle  ;  (4)  hypoglossal  nerve  ;  (5)  posterior  auricular  and  occipital 
arteries  ;  (6)  external  carotid  artery  ;  (7)  stylo-glossus  and  stylo-pharyngeus 
muscles  ;  (8)  stylo-hyoid  ligament  and  pharyngeal  branch  of  the  pneumogastric 
nerve. 

13.  Name  the  branches  of  the  external  carotid  artery  and  indicate  the  territorv 
its  brandies  supply. 

By  the  posterior  auricular,  occipital,  and  temporal  branches  it  supplies  the 
scalp  ;  by  the  superior  thyroid  it  supplies  the  thyroid  gland  and  the  structures 
covering  the  same  ;  by  the  facial  it  supplies  the  dermal  muscles  of  expression 
and  the  skin  covering  them  ;  by  the  lingual  it  supplies  the  tongue  ;  by  the 
internal  maxillary  it  supplies  the  teeth,  the  muscles  of  mastication,  the  palate, 
the  antrum  of  Highmore,  the  nasal  fossae,  and  the  dura  mater ;  by  its  ascending 
pharyngeal  branch  it  supplies  the  pharynx. 

14.  Where  may  you  compress  the  facial  artery? 

In  front  of  the  masseter  muscle  on  the  body  of  the  mandible, 
i  5 .    Where  may  you  find  the  lingual  artery  for  ligation  ? 
Above  the  greater  cornu  of  the  hyoid  bone. 

1 6.  Give  names  of  four  important  structures  in  front  of  the  facial  artery. 

(i)  Hypoglossal  nerve;  (2)  digastric  muscle;  (3)  stylo-hyoid  muscle;  (4) 
submaxillary  gland.  The  fascia  and  skin  lie  in  front  of  these  four  structures. 

1 7.  Name  an  important  branch  of  the  superior  thyroid  artery  found  in  your 
dissection. 

The  superior  laryngeal,  which,  in  company  with  the  superior  laryngeal  branch 
of  the  pneumogastric  nerve,  piercing  the  thyro-hyoid  membrane  to  supply  the 
larynx. 

1 8.  Where  is  the  internal  jugular  vein  made  up  ? 

In  the  jugular  foramen,  by  the  confluence  directly  and  indirectly  of  the  dural 
sinuses.  The  ninth,  tenth,  and  eleventh  nerves  also  pass  out  through  this 
foramen. 

19.  Does  the  internal  jugular  vein  receive  any  tributaries  in  its  course? 

Yes  ;  the  lingual,  facial,  superior  and  middle  thyroid,  and  pharyngeal.  This 
vein  unites  with  the  subclavian  to  form  the  innominate  or  brachio-cephalic  vein. 

20.  What  branches  does  the  pneumogastric  nerve  give  off  in  the  neck  ? 

(i)  The  pharyngeal,  to  help  form  the  pharyngeal  plexus;  (2)  the  superior 
and  recurrent  laryngeal  for  the  supply  of  the  larynx  ;  (3)  the  cervical  cardiac 
branches  to  assist  in  forming  the  cardiac  plexus. 

2 1 .  Where  did  you  find  the  superior  laryngeal  nerve,  and  in  company  with 
zvhat  was  it  ? 

Piercing  and  lying  on  the  thyro-hyoid  membrane  with  the  superior  laryngeal 
branch  of  the  superior  thyroid  artery. 

22.  What  does  the  superior  laryngeal  nerve  supply  ? 

The  mucous  membrane  of  the  larynx  and  trachea  by  its  internal  branch  ; 
the  crico-thyroid  muscle  by  its  external  branch. 

23.  Where  did  you  find  the  recurrent  given  off  and  distributed  / 

It  was  given  off  from  the  vagus  on  the  right  side,  just  after  this  nerve  crossed 
the  subclavian  artery.  The  nerve  then  passed  upward  and  inward,  behind  the 
subclavian  artery,  gained  the  space  next  the  trachea,  and  followed  the  same  to 
the  larynx.  It  supplies  branches  to  all  the  muscles  of  the  larynx  except  the 
crico-thyroid  ;  it  supplies,  also,  branches  to  the  trachea  and  oesophagus. 

24.  What  are  the  glandules  concatenates  and  what  is  their  surgical  importance  f 
The  deep  cervical  glands  accompanying  the  internal  jugular  vein  ;  they  extend 

from  the  base  of  the  skull  to  the  root  of  the  neck.  Their  importance  surgically 
is  the  operation  for  their  removal. 

25.  Name  the  structures  a  surgeon  should  avoid  injuring  in  (his  operation. 


72  PRACTICAL  ANATOMY. 

(i)  The  carotid  artery;  (2)  the  internal  jugular  vein  ;  (3)  the  vagus  nerve  ; 
(4)  the  cervical  sympathetic,  behind  the  carotid  sheath  ;  (5)  the  recurrent 
laryngeal  nerve  ;  (6)  the  apex  of  the  parietal  pleura. 

26.  Name  the  branches  of  the  hypoglossal  nerve. 

(i)  A  communicating  branch  to  the  cervical  plexus  to  form  the  ansa  hypo- 
glossal  loop.  (2)  Muscular  branches  to  the  sterno-hyoid,  omo-hyoid,  sterno- 
thyroid,  thyro-hyoid,  stylo-glossus,  hyo-glossus,  and  genio-hyo-glossus. 

27.  Explain  the  digastric  muscle. 

It  has  an  anterior  belly,  a  posterior  belly,  an  intermediary  tendon.  The 
attachments  are  the  digastric  groove  of  the  temporal  bone  and  the  digastric  fossa 
of  the  mandible,  the  body  of  the  hyoid  bone.  The  action  of  the  muscle  depends 
on  its  fixed  point.  When  the  depressor  muscles  of  the  hyoid  bone  fix  this  bone, 
then  the  digastric  depresses  the  mandible.  In  the  act  of  swallowing,  the  hyoid 
bone  is  elevated  by  the  digastric  and  its  probably  dismembered  synergist,  the 
stylo-hyoid.  The  seventh  nerve  supplies  the  posterior  belly  ;  the  mylo-hyoid 
branch  of  the  inferior  dental  of  the  fifth  nerve,  the  anterior  belly  of  the  digastric. 

28.  What  important  nerve  did  you  find  on  the  outer  part  of  the  liyo-glossus 
muscle  ? 

The  hypoglossal,  the  motor  nerve  of  the  tongue.  The  lingual  artery  passes 
behind  the  muscle. 

29.  Explain  fidly  the  Jiyo-glossus  muscle. 

The  action  of  the  muscle  is  to  make  the  back  of  the  tongue  convex,  and  to 
retract  the  tongue.  The  origin  is  from  the  outer  third  of  the  anterior  part  of 
the  body  of  the  hyoid  bone  and  from  both  the  greater  and  lesser  cornua.  The 
muscle  is  inserted  into  the  side  of  the  tongue. 

30.  Name  the  arteries  you  found  arising  from  the  transverse  part  of  the  aortic- 
arch. 

The  innominate  artery  on  the  right  side  ;  the  left  common  carotid  and  left 
subclavian  on  the  left  side. 

3 1 .  Name  the  stages  of  the  subclavian  artery. 

The  first  stage  is  internal  to  the  scalenus  anticus  muscle  ;  the  second  stage 
is  behind  the  muscle  ;  the  third  stage  is  from  the  outer  margin  of  the  muscle  to 
the  lower  border  of  the  first  rib. 

32.  Name  the  branches  of  the  subclavian  artery. 

(i)  The  internal  mammary  ;  (2)  the  vertebral ;  (3)  the  suprascapular ;  (4)  the 
superior  intercostal ;  (5)  the  transversalis  colli. 

33.  Where  would  you  find  for  ligation  the  internal  mammary  artery  / 

A  finger's  breadth  to  the  right  or  left  of  the  sternum,  in  the  third  or  fourth 
intercostal  space. 

34.  How  does  the  vertebral  artery  get  to  the  base  of  the  brain  / 

It    passes    through    foramina   in    the   transverse    processes    of  the   cervic 
vertebrae,  and  through  the  foramen  magnum. 

35.  If  the  common  carotid  artery  were  ligated,  by  w/iat  tivo  collateral  channels 
ivould  the  blood  circulate  f 

First,  through  the  thyroid  arch.  Second,  through  the  occipito-intercostal 
arch. 

36.  Hoiv  is  the  thyroid  areJi  formed  ? 

By  anastomosis  between  the  superior  thyroid  branch  of  the  external  carotid 
artery  and  the  inferior  thyroid  branch  of  the  subclavian  artery.  (Fig.  38.) 

37.  Hoiv  is  the  occipito-intercostal  arch  formed  / 

By  an  anastomosis  between  the  princeps  cervicis  of  the  occipital,  and  the  deep 
cervical  branch  of  the  superior  intercostal  artery. 

38.  WJiat,  if  any,  changes  occur  in  these  collateral  arches  / 

They  become  much  larger,  since  growth  is  the  correlative  of  function. 


THE  HEAD  AND  NECK.  73 

39.  In  dissection,  where  do  you  find  the  occipito-intercostal  air/i  / 
Between  the  semi-spinalis  colli  and  complexus  muscles.     (Fig.  40.) 

40.  Define  the  word  scalene  and  name  the  scalene  muscles. 

A  triangular  figure  of  unequal  sides.  The  scalenus  anticus,  medius,  and  pos- 
ticus. 

41.  Where  are  these  muscles  inserted  ? 

The  anticus  is  inserted  into  the  scalene  tubercle  of  the  first  rib  ;  the  medius 
into  the  first  rib  ;  the  posticus  into  the  second  rib.  The  two  are  separated  by 
the  subclavian  groove  for  the  subclavian  artery. 

42.  Give  the  origin  of  the  scalene  muscles  according  to  j,  6,  j. 

The  scalenus  anticus  arises  from  the  anterior  tubercles  of  the  transverse  pro- 
cesses of  the  lower  three  ( j) ;  the  medius  from  the  posterior  tubercles  of  the 
lower  six  (6)  ;  the  posticus  from  the  posterior  tubercles  of  the  lower  three  ( j) 
cervical  vertebrae. 

The  cervical  plexus,  to  be  of  technical  as  well  as  practical  value  to  the 
student,  should  be  studied  in  the  following  analytical  manner,  by  question  and 
answer,  before  dissection  : 

1 .  Why  is  this  plexus  called  cervical  ? 

On  account  of  its  derivation  from  cervical  nerves,  its  location  and  major 
distribution  in  the  neck. 

2.  Where  is  this  plexus  situated  ? 

It  is  situated  opposite  the  four  upper  cervical  vertebrae.  It  is  covered  by  the 
sterno-cleido-mastoid  muscle.  It  lies  on  or  is  supported  by  two  muscles  whose 
origin  we  have  just  seen — the  scalenus  medius  and  levator  anguli  scapulae. 

3.  Is  this  plexus  deeply  located? 

No,  it  is  the  most  superficially  located  of  all  the  somatic  plexuses.  It 
emerges  from  under  the  posterior  border  of  the  sterno-cleido-mastoid  muscle 
midway  between  the  origin  and  insertion  of  this  muscle,  regardless  of  length  of 
neck,  into  the  occipital  triangle. 

4.  What  seems  to  be  the  predominating'  function  or  physiological  importance  of 
the  cervical  plexus  f 

To  aid  primarily  and  secondarily  in  respiration,  as  follows  :  It  furnishes  the 
phrenic  nerve.  This  nerve  supplies  the  diaphragm  with  motor  influence  ;  it 
supplies  the  serous  membranes  investing  the  diaphragm  with  sensation  ;  through 
its  relation  to  the  sympathetic  it  reaches  all  the  abdominal  organs  that  contihge 
the  diaphragm.  It  communicates  with  the  nerve  to  the  subclavius  muscle,  and, 
according  to  Hilton's  law,  must  send  articular  branches  to  the  sterno-clavicular 
articulation.  (See  Hilton's  law.)  It  communicates  with  the  intercostals,  by  which 
the  ribs  are  moved  in  re'spiration.  It  communicates  with  the  ansa  hypoglossal 
loop,  by  which  the  depressor  muscles  of  the  hyoid  bone  are  innervated. 

The  cervical  plexus  furnishes  communicating  branches  to  the  formation  of 
the  hypoglossal  loop.  The  hypoglossal  nerve  is  the  motor  nerve  to  the  tongue. 
This  nerve  unites,  by  its  descendens  hypoglossi,  with  the  two  communicantes 
hypoglossi,  previously  referred  to,  and  in  this  way  harmony  is  established 
between  the  nerve  that  moves  the  tongue  and  the  nerve  that  moves  the  muscles 
that  depress  the  hyoid  bone,  on  which  the  tongue  rests. 

The  cervical  plexus  sends  motor  nerves  to  the  following  muscles  :  sterno- 
cleido-mastoid,  scaleni,  the  trapezius,  the  levator  anguli  scapulae  ;  through  its 
descending  cutaneous  branches  it  supplies  the  skin  over  the  insertion  of  these 
muscles.  These  muscles  all  are  accessory  to  respiration  in  asthma  and  other 
diseased  conditions  requiring  more  than  ordinary  tranquil  respiration. 

The  cervical  plexus  communicates  with  the  pneumogastric,  and  this  nerve 
supplies  the  organs  of  voice  and  respiration  with  motion  and  sensation.  In  fine, 
the  function  of  the  cervical  plexus  very  clearly  is  to  innervate  the  muscles  of 
6 


74  PRACTICAL  ANATOMY. 

respiration,  and  to  supply  the  serous  membranes  associated  with  the  respiratory 
movement. 

5 .  How  is  the  cervical  plexus  fanned  / 

It  is  formed  by  the  union  of  the  anterior  primary  divisions  of  the  first, 
second,  third,  and  fourth  cervical  nerves.  The  communications  of  the  upper 
two  nerves  of  this  plexus  are  with  nerves  whose  function  has  to  do  with 
respiration,  with  expenditure  of  air,  or  with  movement  of  the  tongue — the 
sympathetic,  the  pneumogastric,  the  hypoglossal.  The  communications  of  the 
lower  two  nerves  are  with  the.  brachial  plexus. 

6.  Explain  the  distribution  of  the  branches  of  the  cervical  plexus. 

This  is  rational,  and  must  be  studied  in  a  philosophical  light  to  be  remem- 
bered and  appreciated.  Remember,  it  is  one  thing  to  commit  to  memory  a 
statistical  table  of  the  branches  of  distribution  of  this  plexus,  as  is  often  done  ; 
and  quite  another  thing  to  understand  the  rationale  of  a  distribution.  I  desire 
you  to  learn  the  latter  first. 

1 .  This  plexus  has  muscular  branches  which  supply  muscles  that,  without  a 
single  exception,  have  two  well-defined  actions. 

2.  This  plexus  has  branches  that  supply  the  skin  or  serous  membrane,  as 
the  case  may  be,  covering  these  muscles.     This  is  in  accordance  with   Hilton's 
law,  and  applies  to   the  articulations,  and  also  to  the  skin   covering  the  most 
extensive  origin  or  insertion  of  the  muscle. 

3.  This  plexus  has  communicating  branches,  like  any  other  plexus.     One 
set  of  communicating  branches  is  to  those  muscles  which  act  synergistically  to 
produce   the  muscular  movements  of  respiration   directly.     Another  set  is   to 
communicate  with  nerves  that  supply  parts  dependent  on  respiration. 

The  muscles  supplied  are  as  follows  : 

1 .  The  platysma  myoides  acts  toward  clavicle  or  toward  mandible. 

2.  The  sterno-cleido-mastoid  acts  on  the  head  or  the  thorax. 

3.  The  scaleni  act  on  the  ribs  or  on  the  neck. 

4.  The  levator  anguli  scapulae  acts  on  scapula  or  neck. 

5.  The  recti  capitis  antici  major  and  minor  act  on  head  or  neck. 

6.  The  trapezius  acts  on  head  or  shoulder  girdle. 

7.  The  diaphragm  acts  on  ribs  and  on  cervical  fascia. 

8.  Sterno-hyoid  acts  toward  sternum  or  toward  hyoid  bone. 

9.  Omo-hyoid  acts  toward  scapula  or  to  the  hyoid  bone. 

10.  Thyro-hyoid  and  sterno-thyroid  toward  sternum  or  hyoid. 

1 1.  Genio-hyoid  acts  toward  mandible  or  toward  hyoid. 

12.  Genio-hyo-glossus  acts  forward  and  backward. 

13.  Stylo-glossus  acts  to  or  from  the  tongue. 

14.  Hyo-glossus  acts  to  or  from  the  hyoid. 

The  serous  membranes  and  integument  supplied  in  these  areas : 

1.  The  pleura;,  pericardium,  peritoneum. 

2.  Skin  over  the  pectoralis  major  and  acromion  and  clavicle. 

3.  Skin  over  the  depressors  of  the  hyoid  bone. 

4.  Skin  over  the  genial  muscles. 

5.  Skin  over  the  upper  ends  of  sterno-mastoid,  trapezius,  and  scaleni. 

The  phrenic  supplies  all  the  serous  membranes.  The  descending  branches  of 
the  plexus  supply  the  skin  over  the  anterior  part  of  the  upper  thorax  and  over 
the  shoulder.  The  lesser  and  second  occipital  supply  the  skin  over  the  sterno- 
mastoid  and  trapezius.  (Fig.  43.)  The  superficial  cervical  supplies  the  whole 
front  of  the  neck  and  the  region  under  the  chin. 

The  ascending  and  descending  branches,  then,  of  the  cutaneous,  sensory,  or 
superficial  nerves  of  the  plexus  are  thus  accounted  for.  The  supraclavicular, 
suprasternal,  and  supraacromial  are  the  descending  ;  the  superficial  cervical  is  a 


THE  HEAD  AND  NECK. 


75 


transverse  branch  ;  the  great  auricular,  small  occipital,  and  lesser  or  second 
occipital  are  ascending.  These  branches  had  to  undergo  this  very  distribution 
to  carry  out  the  scheme  of  distribution  of  the  cervical  nerves — a  scheme  we 
everywhere  invoke  when  we  would  account  for  sensory  nerve  distribution. 

The  communicating  branches  are  : 

i.  Extrinsic,  as  your  dissection  should  show,  with  the  auriculo-temporal, 
the  facial,  the  intercostals,  the  circumflex,  and  the  great  occipital. 


FIG.  41. — SCHEME  OF  THE  CERVICAL  PLEXUS. 
Note  the  loops  by  which  one  nerve  communicates  with  the  next. 

2.   Intrinsic  :  with  the  hypoglossal,  sympathetic,  pneumogastric,  spinal  acces- 
sory, and  brachial  plexus,  for  reasons  set  forth  in  a  foregoing  paragraph. 


External  and  Internal  Series  of  Muscular  Branches  of  the  Cervical 
Plexus. — The  scalenus  medius,  trapezius,  levator  anguli  scapulae,  and  sterno- 
cleido-mastoid  are,  according  to  the  time-honored  classification,  given  as  the 
external  series,  while  all  the  remaining  muscles  would  naturally  fall  to  the  internal 


76 


PRACTICAL   ANATOMY. 


series.  It  may  be  said,  with  all  deference,  that  this  classification  is  categorical  only. 
It  rests  on  no  basis  of  physiology,  philosophy,  rationalism,  or  even  sense  ;  it  is 
categorical  only.  It  belongs  to  that  part  of  our  nomenclature  that  had  its  origin 
in  fanciful  creations,  and  in  location  only,  like  sphenoid,  ethmoid,  and  external 
iliac.  It  is  tolerated  in  anatomy  and  revered  on  account  of  its  antiquity. 

The  branches  of  the  cervical  plexus,  tabulated  according  to  the  prevailing- 
custom,  but  carried  out  to  their  distribution  to  show  that  these  nerves  are 
physiologically  associated,  directly  or  indirectly,  with  respiration  : 


Filament 
fCtrv. 


J.Ttiree  Sub -scapular  J\/erves. 
2.  Internal  JTnt.T'horacu: 


Mufculo-cutaneeus 

Median. 

•at 


Internal  -cutarwoiif 
Lesser  Internal  cutaneous 


ffom  fitter's  CombenclofJnatomu 


FIG.  42. — SCHEME  OF  THE  BRACHIAL  PLEXUS. 
Note  the  acute  angles  characterizing  the  union  of  nerves. 


SUPERFICIAL  BRANCHES.     (Fie.  43.) 

ASCENDING. — (i)  Second  occipital  supplies  the  skin  over  the  mastoid  insertion  of 
the  sterno-cleido-mastoid.  (2)  Lesser  occipital  supplies  the  skin  of  the  scalp 
over  the  occipital  origin  of  the  trapezius,  and  over  the  greater  insertion  of 
the  sterno-mastoid.  (3)  Great  auricular  supplies  the  skin  over  the  facial 
part  of  the  platysma  and  parotid  gland,  and  over  the  insertions  of  the 
three  dermal  muscles  inserted  into  the  external  ear.  (4)  Superficial  cervical 
supplies  the  skin  over  the  origin  of  the  muscles  arising  from  the  genial 
tubercles,  and  over  the  muscles  inserted  into  the  hyoid  bone. 


THE  HEAD  AND  NECK.  77 

DESCENDING. — (i)  Suprasternal  supplies  the  skin  over  the  origins  of  the  sterno- 
mastoid,  sterno-hyoid,  sterno-thyroid.  (2)  Supraclavicular  supplies  the 
skin  over  the  thoracic  part  of  the  platysma,  and  over  the  costal  attachments 
of  the  scaleni.  (3)  Supraacromial  supplies  the  skin  over  the  omo-hyoid  and 
over  the  clavicular  and  scapular  insertions  of  the  trapezius. 

DEEP  BRANCHES. 

INTERNAL. — (i)  Communicating  branches  to  the  pneumogastric,  hypoglossal, 
sympathetic.  (2)  Muscular  branches  to  the  rectus  capitis  anticus  major  and 
minor,  and  rectus  capitis  lateralis,  and  longus  colli.  (3)  Commumcans 
hypoglossi,  two  cervical  branches  that  unite  with  the  descendens  hypoglossi 
to  form  the  ansa  hypoglossal  loop,  for  the  supply  of  the  depressor  muscles 
of  the  hyoid  bone.  (4)  The  phrenic — a  mixed  nerve  that  supplies  the 
diaphragm  and  the  diaphragmatic  parts  of  the  pericardium,  pleurae,  and 
peritoneum. 

EXTERNAL. — (i)   Communicating  branches  to  the  spinal  accessory  nerve,  in  the 

trapezius  and  under  the  sterno-cleido-mastoid  muscle.      (2)  Muscular  to  the 

trapezius,  levator  anguli  scapulae,  scalenus  medius,  and  sterno-cleido-mastoid. 

The   Brachial  or  Axillary  Plexus. — A  comprehensive  knowledge  of  this 

plexus,  for  dissecting-room  purposes,  must  include  the  following  points  : 

1.  The  formation — by  the  union  of  the  anterior  primary  divisions  of  the  fifth, 
sixth,  seventh,  and  eighth  cervical  nerves,  and  the  greater  part  of  the  first  dorsal 
or  thoracic  nerve. 

2.  The  location  of  emergence  of  the  above — between  the  scalenus  anticus  and 
scalenus  medius  muscles. 

3.  The  communications — which  are  with  the  fourth  cervical ;  with  the  second 
and   third  thoracic   nerves  ;   with  the  phrenic  nerve  ;  with  the  inferior  cervical 
ganglion  of  the  sympathetic. 

4.  The   relations — with   the  subclavian  artery  below  ;  with  the  clavicle  and 
subclavius  muscle  in  front ;  with  the  serratus  magnus  and  subscapular  muscles 
behind. 

5.  The  sheath — formed  by  the  axillary  prolongation  of  the  third  layer  of  deep 
cervical  fascia,  investing  the  plexus  and  axillary  vessels,  and  finally  forming  the 
suspensory  or  axillary  fascia  proper. 

6.  The  formation  of  three  brachial  trunks :  upper,  middle,  and  lower.     The 
upper  by  the  fusion  of  the  fifth  and  sixth  ;  the  middle  by  the  seventh  ;  and  the 
lower  trunk  by  the  eighth  cervical  and  the  greater  part  of  the  anterior  primary 
division  of  the  first  dorsal  nerve. 

7.  The  splitting  of  the  brachial  trunks  into  anterior  and  posterior  brachial 
divisions. 

8.  The  formation  of  the  posterior  cord  by  the  union  of  the  three  posterior 
brachial  divisions. 

9.  The  formation   of  the  outer  cord  by  the   union  of  the  anterior  brachial 
divisions  of  the  upper  and  middle  trunks. 

10.  The  formation  of  the  inner  cord  by  the  anterior  brachial  division  of  the 
lower  trunk. 

1 1 .  The   branches    of  distribution    to    muscles  ;    to    the   skin    covering   these 
muscles   in    general  ;   to  the  skin   covering  the   insertions   of  these  muscles  in 
particular  ;  to  articulations  where  there  is  motion  produced  by  muscles  supplied 
by  the  brachial  plexus. 

12.  The  inosculation  between   sensory  nerves  and  motor  nerves  peripherally. 

13.  Branches  given  off  above  the   clavicle;    branches  thrown  off  below  the 
clavicle,  or  from  the  plexus  proper. 


7  8  PRACTICAL  ANATOMY. 

The  branches  you  will  find  given  off  above  the  clavicle  : 

1.  Muscular  branches   to  the  subclavius,   scaleni,  longus  colli,   rhomboidei, 
as  indicated  in  figure  42. 

2.  A  communicating    branch   to   the  phrenic    nerve.      Follow    the  phrenic 
nerve   up,  on  the   scalenus   anticus  muscle,  and   you  will  find  a  delicate  nerve 
coming  through  the  muscle. 

3.  The  posterior  thoracic  nerve,  also  called  the  long  thoracic,  the  external 


FACIAL  NERVE 


AURICULAR  BR.  OF 

GREAT  AURICULAR 


IfiFRAMANDIB  ULAR 


SUPERFICIAL  CERVICAL 
BRANCHES  OF  SUPER-    ( 
FICIAL  CERVICAL       •{ 
NERVE 


SUPRASTERNAL 


)  BRANCHES  OF 
V         GREA  T 
)     AURICULAR 

(IRE AT  OCCIPITAL 


I.K.1SER  OCCIPITAL 


HREAT  AUSICCLAR 
MASTOID  BR.  OR  and 

SMALL  OCCIPITAL 
SPINAL  ACCESSOR F 

TWIGS  FROM  THE 
•     MASTOID  BRAXCB 

BR.   TO  LKVATOR 

AffGULI  SCAPULA 
Sl'PRA-  A  CR  OMIAL 

S  CPRA  CLA  VICL' LA  R 


BRANCHES  TO 

TRAPEZim 


SL'PRAULA  VICl'LAX 


FIG.  43. — SUPERFICIAL  BRANCHES  OF  THE  CERVICAL  PLEXUS.     (After  Hirschfeld  and  Leveille.) 


phrenic,  and  external  respiratory  nerve  of  Bell,  supplies  the  serratus  magnus 
muscle.  You  will  find  this  nerve  in  the  axillary  space. 

4.  The  suprascapular  nerve  (Fig.  42)  arises  from  the  upper  trunk.  It  passes 
through  the  suprascapular  foramen,  in  the  superior  costa  of  the  scapula  and 
supplies  the  supra-  and  infraspinati  muscles. 

Branches  from  t/ic  UnicJiial  Plexus  /'refer. — Outer  cord:  External  anterior 
thoracic  nerve  to  pectoralis  major ;  outer  head  of  the  median  nerve  fuses  with 
inner  head  from  the  inner  cord  of  the  plexus  ;  musculo-cutaneous  nerve  to 
flexors  of  the  forearm  and  coraco-brachialis. 

Inner  cord  :   Internal  anterior  thoracic  to  pectoralis  minor  ;  inner  head  of  the 


THE  HEAD  AND  NECK.  79 

median  nerve  fuses  with  the  outer  head  from  the  outer  cord  ;  internal  cutaneous 
nerve,  to  inner  forearm  ;  lesser  internal  cutaneous,  to  inner  arm  ;  ulnar  nerve, 
to  forearm  and  hand. 

Posterior  cord :  Three  subscapular  nerves  to  posterior  wall  of  axilla ; 
musculo-spiral  to  the  muscles  of  the  posterior  part  of  arm  and  forearm  ;  circum- 
flex to  the  deltoid  and  teres  minor. 


THE  MOUTH. 

The  structures  seen  in  the  mouth  of  a  patient  are  : 

1.  The  tongue-tip,  dorsum,  and  sides. 

2.  The  dental  arches  and  the  teeth. 

3.  The  vestibule — the  space  outside  the  dental  arches. 

4.  The  frsenum  linguae. 

5.  The  uvula  in  mid-line  of  the  soft  palate. 

6.  Tonsil  in  the  tonsillar  recess.     (Fig.  47.) 

7.  The  palato-glossal  fold  of  mucous  membrane.     (Fig.  47.) 

8.  The  palato-pharyngeal  fold  of  mucous  membrane.     (Fig.  47.) 

9.  The  posterior  pharyngeal  wall. 

10.  The  orifice  of  Stenson's  duct,  opposite  second  upper  molar. 

1 1.  The  general  oral  mucous  membrane. 

12.  The  soft  palate  and  its  subdivisions. 

The  fold  of  mucous  membrane,  the  palato-glossal  fold,  is  supported  by  a 
muscle — the  palato-glossal  muscle.  Also  a  muscle,  the  palato-pharyngeal,  is 
under  the  palato-pharyngeal  fold  of  mucous  membrane.  These  two  muscles 
form  the  anterior  and  posterior  boundaries  of  the  tonsillar  recess,  in  which  is 
found  the  tonsil.  Having  made  yourself  familiar  with  the  physical  appearances 
of  the  above  structures  on  the  living,  find  on  the  cadaver  the  following  : 

1.  The  genio-hyoid  muscle.      (Fig.  47.) 

2.  The  genio-hyo-glossus  muscle.     (Fig.  47.) 

3.  The  stylo-hyoid  muscle.     (Fig.  35.) 

4.  The  stylo-glossus  muscle. 

5.  The  stylo-pharyngeus  muscle. 

6.  The  Eustachtan  orifices  and  pharyngeal  tonsil. 

7.  The  lingualis  muscle.     (Fig.  46.) 

8.  The  tonsil  in  its  recess  ;  between  what  two  muscles  ? 

9.  The  palato-pharyngeal  fold  and  muscle. 

10.  The  palato-glossal  fold  and  muscle. 

1 1.  The  hypoglossal  nerve  (twelfth  cranial).      (Fig.  31.) 

1 2.  The  gustatory  nerve  (lingual  of  fifth  cranial  nerve). 

13.  The  glossal  branch  of  glosso-pharyngeal  nerve.     (Fig.  34.) 

14.  The  chorda  tympani — of  the  seventh  cranial  nerve. 

15.  The  lingual  artery  and  vein.     (Figs.  31  and  47.) 

16.  The  salivary  apparatus  and  blood-supply.     (Fig.  45.) 

17.  The  mylo-hyoid  muscle — the  floor  of  the  mouth.      (Fig.  35.) 

1 8.  The  isthmus  of  the  fauces. 

19.  The  anterior  pillar  =  palato-glossus  muscle.      (Fig.  47.) 

20.  The  posterior  pillar  ==  palato-pharyngeus  muscle.      (Fig.  47.) 

21.  The  azygos  uvula,'  muscle. 

22.  The  levator  palati  muscle. 

23.  The  circumflexus  palati  (tensor  palati). 

How  to  Dissect  the  Tongue.—  The   dissection  of  the  neck,  you  will   recall   by 


8o 


PRACTICAL  ANATOMY. 


examining  your  work,  has  exposed  the  anterior  belly  of  the  digastric  muscle, 
the  hyo-glossus  muscle,  the  mylo-hyoid  muscle,  the  branches  of  the  external 
carotid  artery,  the  hypoglossal  nerve,  and,  to  some  extent,  the  muscles  and  liga- 
ments attached  to  the  styloid  process  of  the  temporal  bone.  To  dissect  the 
tongue  and  mouth  you  proceed  as  follows  :  Retract  the  chin,  saw  through  the  sym- 
physis  menti ;  then,  with  a  sharp  knife,  cut  through  the  center  of  the  tongue  from 
tip  to  hyoid  bone.  You  will  then  see,  separated  by  connective  tissue  areas,  the 
mylo-hyoid,  the  genio-hyoid,  and  the  genio-hyo-glossus  muscles  as  in  figure  44. 
24.  The  boundary  between  the  mouth  and  the  pharynx.  Examine  a  patient 
and  you  will  see  the  soft  palate  hanging  down  between  the  mouth  and  pharynx. 


Stylo-glOBSua 


DORSUM  OF  TONGUE 


Genio-hyo-glossus 
Genio-hyoid 


STYLOID  PROCESS 
Stylo-hyoid 

POSTERIOR  PORTION 
OF  TONGUE 


Cut  edge  of  mylo-hyoid 
/ 

BODY  OF  HYOID  BONE 

11 

/i 

EPIGLOTTIS 

V 

(indicated  by  dotted  Una) 

\\ 

GREATER  CORNU  OF  HYOID  BONE 


Stylo-phary  ngeun 


CARTILAGO  TRITICEA 


Thyro-hyoid 
membrane 


THYROID  CARTILAGE 


Median  portion  of 
crico-thyroid 
membrane 

CRICOID  CARTILAGE 
FIRST  RING  OF  TRACHU 


FIG.  44. — SIDE  VIEW  OK  THE  TONGUE,  WITH  ITS  Mt  SCI.KS. 


The  passage  between  the  two  cavities,  bounded  by  the  tongue,  anterior  pillar  of 
fauces,  and  uvula  is  called  the  isthmus  of  the  fauces.  The  student  should  early 
become  familiar  with  the  soft  palate,  as  its  function  is  complex  and  of  a  very 
interesting  and  practical  nature. 

Study  the  movements  of  the  hyoid  bone  : 

1.  Elevated — by  the  stylo-hyoid  and   digastric   behind  and  the  genio-hyoid 
and  mylo-hyoid  in  front.     These  muscles  are  clearly  antagonistic.     The  former 
are  supplied  by  the  seventh,  the  latter  by  the  twelfth  and  fifth  nerves. 

2.  Forward. — The   genio-hyoid,  when    not  antagonized  by  the  stylo-hyoid, 
pulls  the  tongue  forward. 


THE   HEAD  AND  NECK. 


81 


3.  Backward. — The  stylo-hyoid  and  digastric,  when  not  antagonized  by  the 
mylo-hyoid  and  genio-hyoid,  pull  the  hyoid  bone  backward. 

4.  Downward. — The  depressor  muscles  of  the  hyoid  bone,  when  not  antag- 
onized, pull  the  hyoid  bone  down,  and  with  it  the  tongue.     The  depressors  of  the 
hyoid  bone  are   the  sterno-hyoid,  omo-hyoid,   sterno-thyroid,  and   thyro-hyoid 
muscles.      Their  nerve-supply  is  from  the  ansa  hypoglossal  loop. 

Study  the  simple  movements  of  the  tongue  and  the  muscles  that  produce 
them. 

1 .  Protrusion  beyond  the  teeth  =  deep  part  of  genio-hyo-glossus. 

2.  Retraction  =  superficial  part  of  genio-hyo-glossus. 

3.  Convex  dorsurn  =  hyo-glossi. 

4.  Concave  dorsum  =  inferior  part  of  lingualis  and  stylo-glossus. 

5.  Shorten  tongue  =  the  lingualis. 


SOCIA  PAROTIDIS 


DUCT  OF  SOCIA 
PAROTIDIS 


DUCT  OF  PAROTID 


Bristle  inserted 
into  duct 


Fraenum  linguae 
DUCT  OF  RIVINI 


SUBLINGUAL  GLAND 


DUCT  OF  SUBMAXILLARY 

GLAND 
Mylo-hyoid  muscle 


Anterior  belly  of 
digastric  muscle 


PAROTID  GLAND 


Masseter  muscle 


Sterno-mastoid 
muscle 


Posterior  belly  of 
digastric  muscle 


SUBMAXILLARY  GLAND, 
DRAWN  BACKWARDS 


Loop  of  fascia 


DESP  PORTION  OF  SUBMAXILLARY  GLAND 
FIG.  45. — SIDE  OF  THE  FACE  AND  MOUTH  CAVITY,  SHOWING  THE  THREE  SALIVARY  GLANDS. 

There  may  be  a  great  number  of  compound  movements.  Thus,  the  tongue 
may  be  concave-dorsum,  in  protrusion  or  retraction  ;  convex-dorsum,  the  same. 
In  any  of  the  foregoing  positions  the  whole  organ  may  be  turned  to  either  side, 
or  the  base  may  be  elevated. 

Divide  the  connective  tissue  between  the  genio-hyoid  and  genio-hyo-glossus. 
(Fig.  44.)  The  genio-hyoid  arises  from  the  inferior  genial  .tubercle  of  the 
mandible.  (Fig.  9.)  It  is  inserted  into  the  body  of  the  hyoid  bone. 

The  genio-hyo-glossus  arises  from  the  superior  genial  tubercle.  (Fig.  9.) 
It  has  a  superficial  insertion  into  the  anterior  part  of  the  tongue  ;  a  deep  inser- 
tion into  the  body  of  the  hyoid  ;  above  the  preceding,  of  course.  This  muscle 
produces  the  rapid  protrusion  and  retraction  of  the  tongue. 

The  mylo-hyoid  muscle  forms  the  floor  of  the  mouth.  Divide  the  con- 
nective tissue  between  it  and  the  genio-hyoid.  (Fig.  44.)  This  muscle  arises 
from  the  oblique  line  of  the  mandible — the  mylo-hyoid  ridge.  (Fig.  9.)  A 


82  PRACTICAL  ANATOMY. 

small  part  of  the  posterior  part  of  the  muscle  is  inserted  into  the  body  of  the 
hyoid  bone  ;  the  greater  part  of  the  muscle  is  inserted  into  the  median  line  with 
its  fellow  of  the  opposite  side.  (Fig.  35.) 

Relations  of  the  Mylo-hyoid  Muscle. — Cut  through  the  mucous  mem- 
brane, between  the  border  of  the  tongue  and  the  alveolar  process  of  the 
mandible,  and  you  will  see  the  superior  surface  of  the  mylo-hyoid  muscle.  On 
this  surface  find  : 

1.  The  gustatory  nerve,  the  sensory  (a  branch  of  the  fifth  cranial),  anasto- 
mosing, in  the  substance  of  the  tongue,  with  the  hypoglossal,  the  motor  nerve 
of  the  tongue.     (Fig.  45.) 

2.  Find  the  sublingual  salivary  gland,  communicating,  around  the  posterior 
margin  of  the  mylo-hyoid,  with  the  submaxillary  salivary  gland.     (Fig.  45.) 

3.  Find  the  anterior  belly  of  the  digastric  muscle  (Fig.  35)  under — resting 
upon — the  under  surface  of  the  mylo-hyoid  muscle.     Note  a  branch  of  the  mylo- 
hyoid  nerve   to    this   muscle.     This  muscle  arises  from  the  digastric  fossa   of 
mandible.     (Fig.  9.) 

4.  The  hyo-glossus   muscle   arises  from  the  body  and  both  horns  of  the 

Transverse  muscular  fibres 

PAPILLA 

Superior  lingual 
muscle 


Septum 

Submueous 

^^  tissue 

Inferior  lingual 
muscle,  mixed 
with  extrinsic 
fibre* 

Vertical  muscular  fibres 

FIG.  46. — TRANSVKRSB  SECTION  THROUGH  THE  LEFT  HALF  OF  THE  TONGUE. 

(Magnified.) 
(From  a  preparation  by  Mr.  J.  Pollard,  Middlesex  Hospital  Museum.) 

hyoid  bone.  (Fig.  48.)  It  is  inserted  into  the  tongue.  On  its  outer  surface  find 
the  hypoglossal  nerve.  (Fig.  34.)  On  its  inner  surface  see  the  lingual  artery 
(Fig.  47)  dividing  in  (i)  the  dorsalis  linguae;  (2)  the  ranine  artery.  (Fig.  36.) 

The  Stylo-glossus  and  Stylo-hyoid. — Trace  the  former  to  the  side  of  the 
tongue,  the  latter  to  the  side  of  the  body  of  the  hyoid  bone.  Their  origins  will 
be  seen  at  a  later  stage  of  the  dissection.  (Fig.  48.) 

The  musculi  linguales,  or  proper  intrinsic  muscles  of  the  tongue,  may  be 
studied  in  the  longitudinal  section  (Fig.  46)  to  a  limited  extent  on  your  work. 

Deep  Dissection  of  the  Pterygo-styloid  Region. — In  this  region  you  will  find 
the  following : 

1 .  The  stylo-maxillary  or  stylo-mandibular  ligament,  a  derivative  of  the 
first  layer  of  cervical  fascia,  extending  from  the  styloid  process  of  the  temporal 
bone  to  the  ramus  and  angle  of  the  mandible.     It  is  between  the  masseter  muscle 
and  the  internal  pterygoid  muscle. 

2.  The  temporo-mandibular  articulation,  with  its  interarticular  fibro-car- 
tilage  dividing  the  glenoid  cavity  into  an  anterior  and  a  posterior  synovial  cavity. 


THE  HEAD  AND  NECK.  83 

3.  The  external  pterygoid  muscle,  with  one  insertion  into  the  depression 
in  front  of  the  condyle,  and  another  into  the  interarticular  fibro-cartilage. 

4.  The   internal  pterygoid  muscle,  inserted  into  the  inner  surface  of  the 
ramus.     See  this  muscle  coming  down  from  the  pterygoid  fossa. 


Descending  palatine  artery 
Palato-pharyngeus 

TONSIL 

Ascending  palatine  branch 

of  facial 
Tonsillar  branch  of  dorsalis 

lingual 

Tonsillar  branch  of  facial 
Stylo-gloBsus 

Dorsalis  linguae  artery 

Middle  constrictor 
HYPOGLOSSAL  NERVE 

Facial  artery 

Posterior  belly  of  digastric 
and  stylo-hyoid 
Supra-hyoid  branch 

SUP.  LARYNOEALN. 

Infra-hyoid  branch 
Internal  carotid  artery 


Falato-glossus 


Ranine  artery 


Common  carotid  artery 


FIG.  47. — SCHEME  OF  THE  RIGHT  LINGUAL  ARTERY.     (Walsham.) 


a  inferior / — I 


Lingual! 


Qenio-hyo-glOBBUB 


Genio-hyoid 

Anterior  belly  of 

digastric 


Hyo-glosBus 


Mylo-hyoid 


FIG.  48.— SIDE  VIEW  OF  THE  MUSCLES  OF  THE  TONGUE. 

5.  The  inferior  dental  nerve  and  artery,  between  the  neck  of  the  mandible 
and    the   internal    lateral   ligament   of  the   joint.     This    ligament  you  will   see 
extending  from  the  spine  of  the  sphenoid  to  the  lingula  of  the  mandible  ;   under 
it  are  the  above  structures,  the  inferior  dental  nerve  and  vessels. 

6.  The  internal  maxillary  artery  (Fig.  51),  between  the  neck  of  the  jaw 


PRACTICAL   ANATOMY. 


External  pterygoid 


Internal  pterygoid 


FIG.  49. — THE  PTERYGOID  MUSCI.KS. 


LONG  BUCCAL 
NERVE 


SUB- 

ttANDIBULAR 
GANGLION 

MENTAL 

BRANCH 


ANTERIOR  TEM- 
PORAL NEB  VE 

A  URICULO-TEM- 
PORAL  NERVE 

POSTERIOR  TEM- 
PORAL NERVE 


NERVE  TO  MAS- 
SETER 


CHORDA    TYM- 
PANI 

MYLO-HYOID 

NERVE 
LINGUAL 
NERVE 


DENTAL  XERVB 


l,;.    50.  — DlSTRlHHl'ION    OK    TIIK    MAN  1)1  IHII.AR     DIVISION    OK    TIIK    TRIGKMINAI.    \KRVK.       (Henle.) 


THE  HEAD  AND  NECK.  85 

and  the  spheno-mandibular  ligament.     You  will  see  it  on  the  outer  surface  of  the 
external  pterygoid  muscle. 

7.  The  styloid  process,  muscles  and  ligaments  attached. 

1.  The  stylo-hyoid  muscle. 

2.  The  stylo-pharyngeus  muscle. 

3.  The  stylo-glossus  muscle. 

4.  The  stylo-mandibular  ligament. 

5.  The  stylo-hyoid  ligament. 

Trace  each  from  its  styloid  origin  to  its  specific  insertion. 

Dissection. — The  above  deep  structures  will  be  readily  found  on  dividing  the 
temporo-mandibular  ligament.  As  you  do  this,  notice  the  interarticular  fibro- 
cartilage.  Between  the  neck  of  the  jaw  and  the  internal  lateral  ligament  find 
the  first  stage  of  the  internal  maxillary  artery. 

The  external  pterygoid  muscle  (Fig.  49)  originates  by  two  heads  :  (i)  From 
the  outer  surface  of  the  external  pterygoid  plate.  (2)  From  the  pterygoid  ridge 
on  the  outer  surface  of  the  greater  wing  of  the  sphenoid  bone.  It  has  two 
insertions:  (i)  Into  the  interarticular  fibro-cartilage  of  the  temporo-mandibular 
articulation  ;  (2)  into  a  depression  in  front  of  the  condyle  of  the  jaw. 

The  inferior  dental  nerve  (Fig.  51)  is  a  branch  of  the  inferior  maxillary 
division  of  the  fifth  cranial.  It  passes  between  the  ramus  of  the  jaw  and  the 
spheno-mandibular  ligament,  in  company  with  an  artery  of  the  same  name, 
and  enters  the  inferior  dental  canal.  (Fig.  50.)  It  throws  off  in  its  course 
dental  branches  to  the  teeth  ;  a  large  cutaneous  branch,  the  mental,  to  the 
skin  of  the  chin.  The  mental  branch  comes  to  the  surface  through  the  mental 
foramen.  (Fig.  8.)  The  inferior  dental  artery  takes  the  same  course  and  has  a 
similar  distribution.  (Fig.  51.) 

The  mylo-hyoid  nerve  is  given  off  from  the  inferior  dental  as  the  latter  is 
entering  the  mandibular  canal  in  the  mandible.  It  lies  in  a  groove  on  the  inner 
surface  of  the  lower  jaw,  and  is  covered  by  the  periosteum.  It  supplies  the 
mylo-hyoid  muscle  and  the  anterior  belly  of  the  digastric  muscle  with  motion. 


1 .  What  is  the  buccal  orifice  ? 

A  transverse  slit,  bounded  by  the  lips,  and  terminating  laterally  in  the 
angles  ;  by  it  the  mouth  communicates  with  the  external  world. 

2.  What  is  the  isthmus  of  the  fauces? 

It  is  the  buccal  opening  of  the  pharynx.  It  is  bounded  by  the  tongue  below, 
soft  palate  above,  and  pillars  of  the  fauces  laterally,  and  by  it  the  mouth  com- 
municates with  the  pharynx. 

3 .  Hcnv  is  the  soft  palate  made  up,  and  to  what  is  it  attached  ? 

Its  special  parts  are  :  (i)  The  uvula  ;  (2)  the  anterior  and  posterior  pillars  of 
the  fauces  ;  (3)  the  tonsillar  recess  between  the  pillars.  This  should  be  studied 
on  the  living  subject. 

4.  What  is  the  vestibule  ? 

The  part  of  the  oral  cavity  bounded  by  the  cheeks  and  lips  externally  and 
the  dental  arches  internally. 

5.  What  muscle  lies  under  the  anterior  pillar  of  the  fauces  and  helps  form  the 


same . 


The  palato-glossus  muscle,  very  readily  seen. 
6.    What  is  the  action  of  this  muscle  f 

In  the  act  of  swallowing  it  draws  the  tongue  upward  and  the  anterior  pillars 
downward,  hood-like,  over  the  back  of  the  tongue;  this  closes  the  buccal  orifice 


86 


PRACTICAL  ANATOMY. 


of  the  pharynx  and  prevents  regurgitation  of  ingesta  into  the  mouth,  thereby 
enabling  the  constrictors  of  the  pharynx  to  grasp  the  bolus  to  be  swallowed. 

7.  What  muscle  lies  under  tJie  fold  of  mucous  membrane  of  the  posterior  pillar 
of  the  fauces  ? 

The  palato-pharyngeus.  This  muscle  is  inserted  into  the  superior  cornu  of 
the  thyroid  cartilage,  and  also  into  the  fibrous  part  of  the  pharynx.  The  action 
of  this  muscle  is  to  assist  deglutition  by  elevating  the  pharynx — by  stretching 
the  pharynx  over  the  bolus,  as  it  were. 

The  act  of  swallowing  may  be  compared  to  a  most  delicately  acting  cylinder 
and  piston  :  The  tongue  is  the  piston  ;  the  isthmus  of  the  fauces,  the  cylinder 
in  which  the  piston  plays  ;  the  junction  between  the  pharynx  and  the  oesophagus 


Infraorbital  artery  and  nerve 


Orbital  branch. 


Nasal  branch 
Anterior 
dental  branch  I 

Labial  branch  \ 
Posterior  dental 
branch 


Incisive  branch 
Mental  branch 


Submental  branch 


Spheno-palatine  branch 

Posterior,  or  descending  palatine  branch 
Naso-palatine  branch 

Vidian  branch 

A  nterior  deep  temporal  artery 
External  pterygoid  branch 

I  Posterior  deep  temporal  artery 

Small  meningeal 
artery 

Middle  meningeal 
artery 


Temporal  artery 
Tympanic  branch 

Deep  auricular 

branch 

AriiH'ULO-TEM- 
PORAL  XEKVK 
Masseteric  branch 


External  carotid 
artery 


Internal  lateral  or 
spheno-mandibu- 
lar  ligament 

Afandibular  or 
inferior  dental 
artery  and  nerve 


Succal  branch  with         Internal  pterygoid  branch 
portion  of  buccal  nerve 

Mylo-hyoidean  branch 


FIG.  51.— SCHEME  OF  INTERNAL  MAXILLARY  AKTI.KY. 


is  the  escape.  The  digastric  and  stylo-hyoid  muscles  elevate  the  tongue  ;  at  the 
same  time  the  palato-glossus  draws  the  tongue  backward,  piston-like,  through 
the  isthmus,  thereby  preventing  regurgitation  and  at  the  same  time  pressing 
onward  the  food.  At  this  juncture  the  palato-pharyngeus  muscle  depresses  the 
soft  palate,  thereby  aiding  the  preceding  muscle,  and  at  the  same  time  pulls  up 
the  pharynx,  just  as  one  pulls  a  stocking  on. 

S.  \VIiat  would  be  tlie  result  were  the  poloto-pkaryngfUS  muscle  paralyzed,  and 
do  such  circumstances  arise  in  the  practice  of  medicine  / 

The  result  would  be  loss  of  the  delicate  part  of  the  act  of  swallowing. 
Solids  would  find  their  way  to  the  stomach,  but  fluids,  more  difficult  to  grasp, 
l>y  the  constriction  of  the  pharynx  would  regurgitate  through  the  nose,  under 


THE  HEAD  AND  NECK.  87 

these  conditions,  this  being  the  line  of  least  resistance.  Such  cases  of  regurgita- 
tion  are  met  as  sequels  of  diphtheria. 

9.  Locate  the  tonsil. 

It  is  between  the  anterior  and  posterior  pillars  of  the  fauces  ;  it  corresponds 
in  position  to  the  angle  of  the  jaw  ;  the  superior  constrictor  of  the  pharynx  is 
external  to  it,  while  the  internal  carotid  artery  is  fully  one  inch  from  it.  It  is 
the  ascending  pharyngeal  artery,  between  the  tonsil  and  the  superior  constrictor, 
and  not  the  internal  carotid  artery  that  is  in  danger  of  being  wounded  in  tonsil- 
lotomy. 

i  o.  Explain  the  mylo-hyoid  nerve. 

It  is  a  branch  of  the  inferior  dental,  being  given  off  while  this  nerve  is 
between  the  ramus  and  spheno-mandibular  ligament.  It  pierces  the  spheno- 
mandibular  ligament,  passes  along  the  mylo-hyoid  groove,  and  supplies  the 
anterior  belly  of  the  digastric  and  the  mylo-hyoid  muscle.  This  nerve  is  a  part 
of  the  motor  root  of  the  fifth,  ensconsed  in  the  sheath  of  the  (sensory)  inferior 
dental  part  of  the  fifth,  given  off  from  the  Gasserian  ganglion.  (Fig.  53.) 

1 1 .  Name  and  explain  fully  the  structures  attacked  to  the  styloid  process  of  the 
temporal  bone.     (Fig.  44.) 

There  are  three  muscles  and  two  ligaments:  (i)  The  stylo-hyoid  muscle. 
This  muscle  arises  from  the  back  and  outer  surface  of  the  styloid  process,  near  the 
base.  It  lies  above  the  posterior  belly  of  the  digastric  muscle.  Near  its  inser- 
tion into  the  body  of  the  hyoid,  at  the  junction  of  the  body  and  greater  horn, 
it  bridges  the  intermediary  tendon  of  the  digastric.  In  its  action  it  is  synergistic 
with  the  posterior  belly  of  the  digastric,  the  two  being  supplied  with  motion  by 
the  seventh  nerve.  (2)  The  stylo-glossus  muscle  arises  from  the  front  and  tip  of 
the  styloid  process,  also  from  the  upper  part  of  the  •stylo-mandibular  ligament. 
It  is  inserted  into  the  side  and  under  surface  of  the  tongue.  Its  action  is  to  draw 
the  sides  of  the  tongue  up  to  make  the  dorsum  of  this  organ  concave  from  side 
to  side.  (3)  The  stylo-pharyngeus  arises  from  the  base  of  the  styloid  process, 
opposite  the  stylo-hyoid.  It  is  inserted,  with  the  palato-pharyngeus,  into  the  thy- 
roid cartilage,  and  also  into  and  with  the  constrictors  of  the  pharynx.  (4)  The 
stylo-maxillary  or  stylo-mandibular  ligament  will  be  seen  in  your  dissection  as  a 
process  of  deep  cervical  fascia,  a  derivative  of  the  third  layer,  between  the 
masseter  and  internal  pterygoid  muscles.  It  separates  the  parotid  from  the 
submaxillary  gland.  It  gives  origin  to  one  head  of  the  stylo-glossus  muscle. 
(5)  The  stylo-hyoid  ligament  extends,  as  a  small  elastic  fibrous  cord,  from  the 
tip  of  the  styloid  process  of  the  temporal  bone  to  the  lesser  cornu  of  the  hyoid 
bone.  It  frequently  becomes  ossified.  Occasionally  it  is  of  enormous  size. 

12.  Describe  tJie  external  pterygoid  muscle.     (Fig.  49.) 

This  muscle  has  two  origins  and  two  insertions.  The  upper  head  arises  from 
the  under  surface  of  the  greater  wing  of  the  sphenoid  bone,  limited  internally  by 
the  foramen  ovale,  transmitting  the  third  division  of  the  fifth  nerve,  and  the  fora- 
men spinosum,  transmitting  the  great  meningeal  artery  ;  externally,  the  origin  of 
this  head  is  limited  by  the  pterygoid  ridge.  The  lower  head  arises  from  the 
greater  part  of  the  outer  surface  of  the  external  pterygoid  plate.  The  upper 
head  is  inserted  into  the  interarticular  fibro-cartilage  ;  the  lower  into  the  front  of 
the  condyle.  The  action  of  the  muscle  is  to  draw  the  condyle  well  forward, 
and  with  it  also  the  interarticular  cartilage.  It  also  moves  the  jaw  to  the  oppo- 
site side,  and  assists  to  some  extent  in  opening  the  mouth. 

13.  Describe  tlic  internal  pterygoid  muscle.     (Fig.  49.) 

It  arises  from  the  inner  surface  of  the  external  pterygoid  plate,  and  from  the 
tuberosity  of  the  palate  bone.  It  is  inserted  into  the  inner  surface  of  the  ramus 
of  the  mandible,  limited  above  by  the  mylo-hyoid  ridge  and  inferior  dental  foramen. 
The  action  is  to  close  the  mouth  and  draw  the  jaw  forward  and  to  the  mid-line. 


88 


PRACTICAL  ANATOMY. 


The  nerves  to  the  pterygoid  muscles  are  from  the  third  division  of  the  fifth 
nerve.  (Fig.  53.)  The  blood-supply  comes  from  the  internal  maxillary  artery, 
second  stage.  (Fig.  51.) 


Describe  the  internal  maxillary  artery.     (Fig.  51.) 

First  Stage. — Behind  the  neck  of  the  mandible.      In  this  stage  it  gives  off: 

1.  The  inferior  dental  artery  to  the  inferior  teeth. 

2.  The  great  meningeal  artery  to  the  dura  and  calvarium. 

3.  The  small  meningeal  artery  to  the  dura  mater. 

4.  The  deep  auricular  branch  to  external  canal. 

5.  Tympanic,  to  the  membrana  tympani. 


Temporal 


Buccinator 


FIG.  52. — THE  TEMPORAL  MUSCLE. 

The  second  stage  of  the  artery  gives  off  branches  to  muscles  of  mastication 

1.  Deep  temporal  branches  to  temporal  muscles. 

2.  Buccal  branch  to  the  buccinator  muscle. 

3.  Internal  pterygoid  branch  to  internal  pterygoid  muscle. 

4.  External  pterygoid  branch  to  external  pterygoid  muscle. 

5.  Masseteric  branch,  to  the  masseter. 

The  second  or  pterygoid  stage  lies  on  the  outer  surface  of  the  external  ptery- 
goid muscle,  under  cover  of  the  temporal  muscle  and  the  ramus  of  the  mandible. 

The  third  stage  of  the  artery  gives  off  these  branches  : 

i.  The  posterior  superior  dental  artery.  This  is  confusing,  and  requires  an 
explanation.  The  dental  branches  supply  the  teeth.  They  enter  the  posterior 
superior  dental  canals,  through  foramina  on  the  posterior  surface  of  the  body  of 
the  superior  maxilla.  The  alveolar  branches  supply  the  gums.  Some  branches 
supply  the  mucous  membrane  of  the  antrum  ;  these  might  be  called  antral 
branches. 


THE   HEAD   AND   NECK. 


89 


2.  The  infraorbital  artery  enters  the  infraorbital  canal  in  the  floor  of  the  orbit. 
It  appears  on  the  face  as  the  infraorbital.      It  gives  branches  to  the  anterior  teeth. 
These  latter  pass  through  the  anterior  superior  dental  canals  in  the  anterior  wall 
of  the  antrum. 

3.  Descending   palatine   passes  through   the  posterior  palatine  canal,  along 
the  roof  of  the  mouth,  to  the  foramen  of  Stenson,  where  it  anastomoses  with  the 
naso-palatine  artery.      It  accompanies  the  anterior  branch  of  Meckel's  ganglion. 

4.  The  spheno-palatine  passes  through  the  spheno-palatine  foramen  into  the 
cavity  of  the   nose.      It   divides   into  the   naso-palatine   branch  to   the  septum, 


FIG.  53. — SCHEME  OF  THE  DISTRIBUTION  OF  THE  FIFTH  CRANIAL  OR  TRK;F.MINAL  NERVE. 
Notice  especially:    (l)   The  recurrent  branch  from  the  Gasserian  ganglion  to  the  dura  of  the  middle  fossa 
and  tentorium.      (2)  Filaments  from  the  carotid  plexus.      (3)  The  motor  root  of  the  fifth  nerve  behind 
the  ganglion,  but  independent  thereof.      (4)   The  formation  of  the  otic,  submaxillary,  Meckel's,  and 
the  ciliary  ganglion. 

which   anastomoses   with   the    descending   palatine    artery,   and    some    external 
branches  to  the  lateral  walls  of  the  nose. 

5.  The  Vidian  nerve  passes  through  the  Vidian  canal  with  the  Yidian  nerve. 
It  is  distributed  to  the  pharynx  and  Eustachian  tube. 

6.  The  pterygo-palatine   passes   through   the  pterygo-palatine  canal.     It   is 
distributed  to  the  upper  part  of  the  pharynx  and  Eustachian  tube. 

Describe  tJie  inferior  maxillary  division  of  t/te  fifth  cranial  nerve. 
It   passes  through   the  foramen   ovale  with  the  small  meningeal  artery.     It 
gives  off  the  following  branches  : 

i.    Muscular  branches  to  all   the  muscles  of  mastication.     These  accompany 
7 


9° 


PRACTICAL    ANATOMY. 


muscular  branches  of  the  internal   maxillary  artery  and   take  the   name  of  the 
muscles. 

2.  The  auriculo-temporal  nerve.     (Fig.  53.)     The   middle  meningeal   artery 
passes    between  the  two   roots   of  this   nerve.     This   nerve  gives   an  articular 
branch  to  the  temporo-mandibular  articulation.      It  does  this  in  accordance  with 
Hilton's   law.      It   gives    branches    to    the   external    auditory    meatus    and    the 
membrana  tympani,  and  is  often  responsible  for  ear-ache  in  children.      It  sends 
branches  to  the  scalp,  with  the  temporal  arteries,  and  may  be  the  terminus  of 
visceral  reflexes  in  the  scalp. 

3.  The  inferior  dental  nerve  to  (i)  the  teeth  of  the  mandible  ;  (2)  to  the  skin 
of  the  chin  (mental  nerve)  ;  (3)  to  the  anterior  belly  of  the  digastric ;  and  (4)  to 
the  mylo-hyoid  muscle,  through  the  mylo-hyoid  nerve. 

4.  The  gustatory  or  lingual  nerve,  the  great  sensory  nerve  to  the  tongue. 
It  anastomoses  in  the  tongue  with  the  hypoglossal  and  the  glossal  branch  of  the 
glosso-pharyngeal  nerve.      Special  notice  must  be  given  this  nerve,  on  account 


STYLOID  PROCESS 


(i  LOSSO-PHA  R  YN- 
GEAL  NERVE 

HYPOOLOS8AL 

.v /•;/.•  i  '!•: 

Occipital  artery  — 

HUB  MAXILLARY 
GANGLION 

DUCT  OF  SUBMAXILLARY  GLAND 


Middle  constrictor 
muscle 


l.ini/iKil  iir/i'rt/ 


/-:.sr/.;.v/>/-;.y,s  .\o.\j 
NERVB 


Fir..  54. — MUSCLES,  VKSSKLS,  AND  NERVKS  OK  THK  TON<;I;K. 

of  (i)  the   chorda  tympani  nerve;  (2)  the    submaxillary  ganglion  ;   (3)  the  ot 
ganglion. 

The  chorda  tympani  nerve  (Fig.  54)  is  a  branch  of  the  seventh  cranial 
nerve.  It  passes  through  the  tympanum.  It  leaves  this  cavity  by  the  canal 
of  Huguier  in  the  petrous  portion  of  the  temporal  bone.  It  passes  between  the 
two  pterygoid  muscles.  It  meets  the  lingual  nerve,  and  accompanies  this  to 
the  submaxillary  gland.  This  nerve  gives  branches  to  the  sublingual  gland,  the 
lingualis  muscle,  and  the  submaxillary  ganglion. 

The  Submaxillary  Ganglion.     (Fig.  54.) 

(rii'C  location  of  the  subma.villary  ganglion. 

It  is  on  the  outer  surface  of  the  hyo-glossus  muscle,  attached  to  the  gustatory 
or  lingual  nerve.  The  ganglion  is  about  the  si/e  of  a  pin's  head. 

Name  the  roots  of  the  ganglion  nn<1  give  their  source. 

1 .  Scnsorv  root  is  from  the  gustatory  nerve,  a  branch  of  the  fifth  nervr. 

2.  Motor  root  is  from  the  chorda  tympani,  a  branch  of  the  seventh  nerve. 

3.  Svmfwtltetic  root  is  from  the  nervi  molles — the  facial  sympathetics. 


THE  HEAD  AND  NECK. 


91 


Its  branches  are  distributed  to  the  mucous  membrane  of  the  floor  of  the 
mouth  and  to  the  submaxillary  gland  and  its  duct. 

The  otic  ganglion  (Fig.  53)  is  on  the  inferior  maxillary  division  of  the  fifth 
nerve.  Its  roots  are  : 

1.  Motor,  from  the  inferior  maxillary  division  of  the  fifth  nerve. 

2.  Sensory,  from  the  auriculo-temporal  branch  of  the  fifth  nerve. 

3.  Sympathetic >  from  a  plexus  on  the  middle  meningeal  artery. 
Give  tJie  location  and  relations  of  the  otic  ganglion. 

(i)  External  to  it  is  the  inferior  maxillary  nerve  ;  (2)  Internal  to  it  is  the  circum- 
flexus  (tensor)  palati  muscle  ;  (3)  posterior  to  it  is  the  middle  meningeal  artery. 

Aside  from  the  three  root  communications  previously  given,  has  the  otic 
ganglion  any  other  communications  ? 

Yes  ;  it  communicates  with  the  seventh  or  facial  nerve  and  with  the  glosso- 
pharyngeal  by  the  lesser  petrosal  nerve. 


ANTERIOR  DENTAL        MAXILLARY  NERVE        ORBITAL  BRANCH 


MA  X1LLA  R Y  NER I  'E 


MECKEUS  GANGLION 


POSTERIOR  DENTAL 


LOOP  FORMED  BY  MIDDLE  AND  ANTERIOR  DENTAL  NERVES 
FIG.  55. — THK  MAXILLARY  NERVE  SEEN  FROM  WITHOUT.     (Beaunis. ) 

To  what  muscles  are  the  branches  of  the  otic  ganglion  distributed  ? 
To  the  tensor  palati  and  tensor  tympani. 

Describe  the  superior  maxillary  division  of  the  fifth  cranial  nerve.      (Fig.  55.) 
This  nerve,  a  branch  of  the  Gasserian  ganglion,  leaves  the   cranium  by  the 
foramen  rotundum  in  the  greater  wing  of  the  sphenoid  bone.     The  nerve  crosses 
the  spheno-maxillary  fossa,  enters   the  orbit  by  the  spheno-maxillary  fissure, 
traverses   the  infraorbital  canal  in  the  floor  of  the  orbit,  appears   on   the  face  at 
the  infraorbital  foramen,  and   here  communicates  with  the  infraorbital  branch  of 
the  seventh  nerve  to  form  the  infraorbital  plexus. 
Its  branches  are  both  numerous  and  important : 
i.   The  nasal,  labial,  and  palpebral  on  the  face.      (Fig.  53.) 
Anterior  superior  dentals  to  incisor  teeth.      (Fig.  53.) 
Posterior  superior  dentals  to  molar  teeth.      (Fig.  53.) 

4.  Spheno-palatine  branches  to  Meckel's  ganglion.      (Fig.  53.) 

5.  Temporo-malar  are  cutaneous  to  the  cheek  and  temple. 
A  recurrent  meningeal  branch  to  the  dura.      (Fig.  53.) 


2. 

3- 


6. 


92  PRACTICAL  ANATOMY. 


Two    CASES   OF  REFLEX  PAIN. 

A  Patient  has  Pain  in  tJic  Auditory  Canal — On  examination  you  find  no 
local  objective  symptoms.  Where  may  the  real  seat  of  the  trouble  be  located  ? 
The  auditory  canal  is  supplied  by  the  auriculo-temporal  branch  of  the  fifth 
cranial  nerve.  The  irritation  may  be  sought  for  anywhere  in  the  distribution  of 
this  nerve,  but,  logically,  those  parts  of  the  fifth  nerve  which  experience  has 
proved  are  most  liable  to  disease  and  injury  should  be  interrogated  first.  We 
may  venture  the  assertion  that  the  teeth,  nose,  eye,  tongue,  and  antruin  of  High- 
more  represent  about  the  order,  in  point  of  frequency.  Here,  then,  is  the 
specialist  invoked,  since  a  carious  tooth,  an  irritated  gum,  a  septal  spur,  eye 
strain,  a  lingual  ulcer,  or  pus  in  the  antrum  of  Highmore  may  be  the  immediate 
exciting  cause  of  the  pain  in  the  auditory  canal.  Conversely,  a  patient  may  have 
a  violent  toothache,  and  examination  may  reveal  neither  exposed  pulp  nor  irri- 
tated gum.  Conservative  dentistry  in  this  case  would  refer  a  patient  to  other 
specialists,  whose  field  of  usefulness  lies  in  the  distribution  of  the  fifth  pair  of 
cranial  nerves,  primarily  or  secondarily,  since  reflex  pain  may  be  primary  and 
secondary. 

What  is  meant  by  primary  and  secondary  reflex  pain  f 

The  expression  is  a  coinage,  explained  as  follows  :  Where  a  carious  tooth 
manifests  pain  in  the  ear,  eye,  nose, — anywhere  in  organs  supplied  by  the  same 
nerve  direct, — this  is  called  primary  ;  where,  however,  a  carious  tooth  manifests 
pain  in  distant  regions,  not  supplied  by  the  fifth  nerve,  but  connected  therewith 
by  communicating  branches,  this  is  called  secondary.  Let  the  following  cases 
illustrate  the  point  and  apologize  for  the  coinage  : 

1.  A  patient  consulted  a  prominent  dentist  in  this  city  for  intractable  pain  in 
a  molar  tooth.      Examination  revealed  no  objective  symptoms  of  disease.     The 
patient  was  advised  to  consult  other  specialists  in  the  primary  radius  of  the  fifth 
pair  of  nerves — viz.,  the  eye,  nose,  ear,  or  throat  man.      The  patient  disregarded 
the  specific  character  of  the  advice,  and  consulted  a  specialist  in  the  secondary 
radius  of  the  fifth  nerve,  the  gynaecologist,  who  removed  an  ovarian  tumor.    The 
pain  in  the  molar  did  not  return. 

2.  Hilton  reports  a  case  from  Romberg  of  cough  and  vomiting  which  ceased 
only  after  a  pruritus  of  the  external  auditory  meatus  was  cured.     The  nerves 
concerned  in  this  case  were  the  vagus  and  the  trigeminus. 

The  general  practitioner  of  medicine  who  facetiously  disclaims  confidence  in 
reports  of  "  toothache  in  the  ear,  and  earache  in  an  ovary,"  as  he  is  wont  to  call 
such  cases,  is  placing  himself  on  record  with  those  who  a  few  years  ago  hooted 
at  asepsis.  Pain  is  a  projectile,  and  specialists  in  medicine  to-day  are  doing  more 
than  any  one  else  to  harmonize  physiological  speculations  and  anatomical  nerve- 
distributions  and  nerve-communications,  by  furnishing  clinical  evidence  of  that  line 
of  least  resistance  which  pain,  as  a  projectile,  must  follow.  The  student  of  prac- 
tical anatomy  is  urged  to  give  special  attention  to  those  parts  of  nerve-trunks 
recorded  in  the  text-books  as  communicating  branches,  for  upon  these  depends 
the  rationale  of  reflexes,  on  which  so  much  is  said  and  written. 

The  Glosso-pharyngeal  Nerve  (Fig.  54). — You  will  find  this  nerve  between 
the  jugular  vein  and  internal  carotid  artery.  It  lies  above  the  superior  laryngeal 
nerve,  on  the  stylo-pharyngeus  muscle  and  superior  constrictor  of  the  pharynx. 
It  is  distributed  to  the  back  of  the  tongue  and  to  the  pharynx.  This  nerve  is 
deeply  located.  It  can  not  be  mistaken.  It  is  the  ninth  cranial  nerve.  It 
leaves  the  base  of  the  cranium  by  the  jugular  foramen  with  the  tenth  and  eleventh 
nerves  and  the  jugular  vein. 


THE   HEAD  AND  NECK.  93 


THE  MUSCLES  OF  MASTICATION. 

TJic  muscles  of  mastication  are  the  temporal,  buccinator,  the  internal  and 
external  pterygoids,  and  the  masseter.  (Figs.  56  and  57.)  These  are  the  power- 
ful muscles  that  act  on  the  mandible,  by  whose  action  the  food  is  cut  by  the 
incisors,  torn  by  the  canines,  and  triturated  by  the  molars.  It  would  seem  that 
the  muscles  that  depress  the  jaw  belong  to  the  same  category;  hence  we  will 
consider  them  incidentally  here,  in  detail  in  another  section. 

The  temporal  muscle  (Fig.  52)  arises  from  the  complete  temporal  ridge, 
from  the  temporal  fossa,  and  from  the  under  surface  of  the  temporal  fascia.  It 
is  inserted  into  the  coronoid  process  of  the  mandible,  as  far  forward  as  the  last 
molar  tooth.  The  muscle  is  triangular  ;  hence,  according  to  rule,  it  will  be  found 
taking  its  nerve-supply  near  the  apex.  It  derives  its  nerve-supply  from  the 
third  division  of  the  trigeminus.  (Fig.  53.)  In  your  dissection  you  find  this 
muscle  related  superficially  to  the  arcus  zygomaticus,  the  temporal  fascia,  the 
temporal  branches  of  the  seventh  nerve,  the  superficial  temporal  arteries  and 
veins,  and  the  auriculo-temporal  branch  of  the  fifth  nerve.  (Figs.  15-17.) 
Deeply  the  muscle  is  related  to  the  temporal  fossa  and  the  external  pterygoid 
muscle. 

The  buccinator  muscle  (Fig.  62)  arises  from  the  alveolar  processes  above 
the  upper  and  below  the  lower  molar  teeth  of  the  upper  and  lower  jaws  respec- 
tively ;  and  from  the  pterygo-maxillary  ligament.  It  is  inserted  into  the  outer 
part  of  the  orbicularis  oris.  Its  function  is  (i)  to  draw  the  corners  of  the  mouth 
outward  and  backward  against  the  teeth  ;  (2)  to  antagonize  the  tongue  by  per- 
mitting no  food  to  be  pushed  by  this  organ  beyond  the  dental  arches,  into  the 
vestibule  during  mastication. 

The  internal  pterygoid  muscle  (Fig.  '57)  arises  from  the  inner  surface  of  the 
external  pterygoid  plate,  from  the  tuberosity  of  the  palate  bone.  It  is  inserted 
into  the  inner  surface  of  the  ramus  of  the  mandible,  as  high  as  the  inferior  dental 
foramen  and  mylo-hyoid  groove.  The  muscle  is  quadrangular  ;  hence,  according 
to  rule,  it  takes  its  nerve-supply  in  the  centre.  The  action  of  the  muscle  is  to 
close  the  mouth  and  draw  the  jaw  forward  and  to  the  mid-line. 

Name  the  agents  thai  depress  the  lower  jatv. 

The  digastric  muscle,  the  platysma  myoides,  and  gravity. 

/  ?  'liicJi  muscles  act  on  the  mandible,  to  protrude  the  lower  ja^iv  ? 

The  external  pterygoid  muscle  and  the  superficial  part  of  the  masseter 
muscle. 

Hoiv  is  the  mandible  returned  to  its  original  position  in  the  glcnoid  ? 

It  is  drawn  back  by  the  posterior  fibres  of  the  temporal  muscle,  and  by  the 
deep  fibres  of  the  masseter  muscle. 

\  \  liat  are  the  ifiuscles  of  trituration  ? 

The  external  pterygoids.  They  act  alternately,  drawing  the  mandible 
forward  and  to  the  opposite  side  :  this  movement  produces  trituration. 

WJiat  is  the  function  of  the  temporal,  masseter,  and  internal  pterygoid  muscles  ? 

They  raise  the  mandible  against  the  upper  jaw  with  great  force. 

Has  the  temporal  muscle  an  independent,  specific  action  ? 

Yes,  its  specific  action  is  to  accentuate  incision.  The  quick  snapping  move- 
ment of  the  jaw  is  done  by  this  muscle. 

What  is  meant  by  superficial  and  deep  part  of  the  masseter  muscle  / 

Your  knowledge  of  the  action  of  the  masseter  muscle  on  the  mandible  is 
imperfect  without  an  understanding  of  these  two  parts  :  In  reality  each  masseter 
is  two  muscles.  Each  part  of  the  masseter  muscle  has  a  separate  origin,  separate 
function,  separate  insertion.  One — the  superficial — is  strong,  tendinous,  and 


94 


PRACTICAL  ANATOMY. 


active  in  assisting  the  external  pterygoid  muscle,  in  drawing  the  lower  molars 
across  the  upper  molars,  in  trituration  of  food  ;  the  other — the  deep  portion — 
is  weak,  broad,  muscular,  and  almost  passive  in  assisting  the  posterior  segment 
of  the  temporal  muscle  in  bringing  the  mandible  back  to  its  position,  preparatory 
to  another  movement  of  trituration. 

The  specific  origins  and  insertions  of  these  separate  parts  of  the  masseter 
muscle  make  possible  the  separate  physiological  functions,  as  above  indicated. 
Study  them  separately,  as  follows  : 

The  superficial  part  of  the  masseter  (Fig.  56)  muscle  arises:   (i)  From 


Corrugatpr 
supercilii 


Fyramidalis 

Levator  labii 

Buperioris 

alaequc  nasi 

Levator  labii 

Buperioris 

Compressor 

uarium 
Levator  anguli 

oria 

Naso-labialis 
Depressor  alae 

nasi 
Orbicularis  oris 

Buccinator 

Depressor 

anguli  oris 

Depressor  labii 

inferioris 
Levator  menti 
Mylo-hyoid 

Anterior  belly  of 
digastric 


Temporal 


Zygomaticus 
major 


Posterior  belly 
of  digastric 

Splenius  capitis 

Stylo-hyoid 

Sterno-mastoid 


Levator  anguli 
scapulae 


Scalenus  anticus 


IMC.  56 — '1'iiK.  DKH-F.K   LAYKK  01    nil-.  Mr-ri.Ks  01    TMK  FACE  AND  NKCK. 

the  malar  process  of  the  superior  maxilla  by  a  strong  tendon  ;  (2)  from  the 
anterior  two-thirds  of  the  lower  border  of  the  /.ygomatic  arch.  From  this  strong 
origin  the  fibres  pass  backward  and  downward  to  their  insertion  into  the  lower 
half  and  angle  of  the  outer  surface  of  the  ramus.  (Fig.  58.)  The  action  is  to 
draw  the  mandible  forward.  The  synergist  of  this  segment  of  the  masseter  is 
the  external  pterygoid. 

The  deep  portion  of  the  masseter  (Fig.  56)  muscle  arises :  (i)  From  the 
inner  surface  of  the  /.ysj,omatic  arch  ;    (2)  from  the  lower  border  of  the  posterior 


THE  HEAD  AND  NECK. 


95 


third  of  the  zygoma.  This  portion  is  inserted  into  the  upper  half  of  the  outer 
surface  of  the  ramus.  (Fig.  58.)  Its  action  is  to  assist  the  posterior  segment 
of  the  temporal  muscle  in  drawing  the  mandible  backward. 

The  external  pterygoid  muscle  (Fig.  57)  originates  when-  and  is  hcnv 
inserted  ? 

The  function  of  this  muscle  is  second  to  none,  hence  its  bony  and  cartil- 
aginous attachments  merit  special  notice.  Here,  as  in  the  preceding  case,  there 
are  in  reality  two  muscles.  They  are,  however,  described  as  upper  and  lower 
heads  of  one  muscle. 

The  upper  head  arises  from  the  pterygoid  ridge  on  the  outer  and  under  surface 
of  the  greater  ala  of  the  sphenoid  bone.  Its  specific  insertion  is,  according  to  my 
experience,  confined  to  the  interarticular  fibre-cartilage  of  the  temporo-mandibular 
articulation.  The  function  would  seem  to  be  to  regulate  the  movements  of  this 


External  ptefygoid 


Internal  pterygoid 


FIG,  57. — THE  PTEKVCOID   MTSCI.KS. 


cartilage  to  the  sliding  of  the  condyle  forward  on  to  the  eminentia  articularis 
when  the  mouth  is  opened.  The  only  apparent  use  of  the  interarticular  cartilage 
is,  when  the  mouth  is  opened,  to  furnish  a  cup  concavity  for  the  condyle  while 
this  latter  is  gliding  over  the  convex  eminentia  articularis.  (Fig.  58.) 

A  cracking  noise  on  opening  the  mouth  is  frequently  both  a  subjective  and 
an  objective  symptom.  This  noise  is  beyond  doubt  produced  by  temporary 
paralysis  of  this  part  of  the  external  pterygoid,  the  condyle  overriding  the  margin 
of  cartilage  that  normally  should  precede  tire  same.  The  rational  treatment 
would  seem  to  be  fixation  of  the  cartilage  in  the  position  it  occupies  when  the 
mouth  is  open. 

Conclusion  :  The  function  of  the  upper  head  of  the  external  pterygoid  is  to 
make  tense  and  carry  forward  the  interarticular  fibre-cartilage.  The  function 
of  the  lower  head  is  to  most  powerfully  draw  the  jaw  forward. 

The  loiter  /icad  of  the  external  pterygoid  muscle  arises  from  the  outer  surface 


96  PRACTICAL  ANATOMY. 

of  the  external  pterygoid  plate,  except  a  small  strip  at  its  lower  and  front  part 
It  is  inserted  into  the  depression  in  front  of  the  neck  of  the  condyle.  (Fig.  58.) 
The  action  of  this  head  is  to  draw  the  condyle  forward  ;  at  the  same  time  the 
upper  head  draws  the  cartilage  forward. 

Concerning  the  noise  patients  frequently  hear  on  opening  the  mouth,  I  would 
say  I  can  not  now  recall  ever  having  read  or  heard  a  rational  explanation  of  its 
occurrence.  The  theory  I  advance  above  is  more  for  the  purpose  of  getting  the 
student  aroused  to  the  necessity  of  learning  the  origins  and  insertions  of  the 
pterygoids  than  for  mere  theorizing.  If  I  succeed  even  in  this,  the  object  of  this 
paragraph  will  have  been  accomplished.  I  found  a  cadaver  in  which  the  crack- 
ing noise  attended  every  time  the  mouth  was  passively  opened.  On  dissection 
I  found  the  cartilage  had  contracted  inflammatory  adhesions  to  the  dome  of  the 
glenoid  cavity.  It  was  on  this  single  case  I  founded  the  theory  above  advanced, 
in  lieu  of  an  explanation  for  those  noises  in  the  temporo-mandibular  articulation 
concerning  which  every  physician  and  dentist  has  been  consulted  by  solicitous 


EMINENTIA  ARTICULARIS 


POSTERIOR  GLENOID  TUBERCLE 


CORONOID  PROCESS 


GLENOIO  SYNOVIAL  CAVITIES 


Interarticular  flbro-cartil- 
age  into  which  is  in- 
serted the  upper  head  of 
the  external  pterygoid 

Insertion  of  the  lower  head 
of  the  external  pterygoid 


Insertion  of  the  deep  layer 
of  the  masseter  muscle 


Insertion  of  the  superficial 
layer  of  the  masseter  mus- 
cle 


FIG.  58. — SCHEMATIC.     TEMPORO-MANDIBULAR  ARTICULATION. 

This  is  assumed  to  represent  the  normal  relation  of  condyle  of  mandible,  and  interarticular  cartilage  to  the 
*  eminentia  articularis  when  the  mouth  is  closed. 


patients.     A  single  case,  however,  is  a   mere  bagatelle  ;    numerous    cases   by 
different  observers  will  be  necessary  to  give  the  theory  scientific  sanction. 

///  dislocation  of  the  condyle  of  the  mandible,  what  muscles  must  be  overcome  / 

Practically  all.  Theoretically,  the  posterior  part  of  the  temporal  and  the  deep 
portion  of  the  masseter.  As  a  matter  of  philosophy,  however,  malposition  of 
the  head  of  a  bone  immediately  sets  up  tonic  contraction  in  all  the  muscles  of 
the  group,  since  pain  in  the  joint  is  reported  to  the  brain  and  contraction  follows 
in  all  the  muscles  in  the  articular  nerve  circuit.  See  Hilton's  law  in  the  intro- 
ductory chapter. 

The  temporal  muscle  has  practically  two  portions  :  an  anterior  and  a  pos- 
terior. The  latter  pulls  the  jaw  backward  ;  the  former,  acting  alone,  would  pull 
the  jaw  forward. 

What  are  tJie  propositions  in  tlic  nerve -supply  to  the  mitsc/cs  of  mastication  f 

They  are  : 

i.    Nerve-supply,  sensory,  both    to  the  pulp  of  the  teeth   and  to  the  gum 


THE  HEAD  AND  NECK. 


97 


EMINENTIA  ARTICULARIS 


Interarticular  flbro- 
cartilage 


MANOIBULAR  CONDYLE 


FIG.  59. — SCHEMATIC.     TEMPORO-MANDIBULAR  ARTICULATION. 

This  is  assumed  to  represent  relation  of  condyle  and  cartilage  to  eminentia  articularis  when  the  mouth  is 
open.  Here  both  condyle  and  cartilage  slide  forward  on  to  the  eminentia  articularis ;  the  former 
by  action  of  the  lower,  the  latter  by  action  of  the  upper,  head. 


EMINENTIA  ARTICULARIS 


Upper  head  of  external 
pterygoid 


Lower  head  of  external 
pterygoid 


GLENOID  SYNOVIAL  CAVITY 


CONDYLE  UNATTENDED  BY  THE  CARTILAGE  ON 
THE  EMINENTIA  ARTICULARIS 


FIG.  60. — SCHEMATIC.     TEMPORO-MANDIBULAR  ARTICULATION. 

This  is  assumed  to'  represent  abnormal  relation  of  condyle  and  cartilage  to  eminentia  articularis  in  those 
cases  where  the  nerve-twig  that  supplies  the  upper  head  of  the  external  pterygoid  muscle  is  paralyzed. 
A  cracking  noise  on  opening  the  mouth  is  a  symptom.  Here  the  cartilage  remains  back  in  the 
glenoid,  there  being  nothing  to  pull  it  forward.  The  condyle  slips  over  the  thick  margin  and  pro- 
duces the  noise. 


98  PRACTICAL   ANATOMY. 

covering  the  same.     This  comes  from  the  fifth  cranial  nerve,  through  dental  and 
gingival  branches  respectively. 

2.  Nerve-supply,  motor,  to  the  muscles  that  elevate  the  jaw,  and  sensory,  to 
the  skin  covering  these  muscles.     This  is  from  the  fifth  cranial  nerve. 

3.  Nerve-supply,    sensory,   to    the    articulation  moved    by  the    muscles    of 
mastication — the  temporo-mandibular  articulation.      This  is  from   the  auriculo- 
temporal  branch  of  the  fifth  cranial  nerve.     This  is  explained  by  Hilton's  law. 

4.  Nerve-supply,  sensory,  to  the  roof  of  the  mouth.     This  is  from  the  fifth 
through    Meckel's   ganglion.     Also    the   sensory   nerve-supply   to   the   tongue. 
The  greater  part  of  this  is  from  the  fifth  nerve  through  the  lingual  branch. 

5.  Nerve-supply  to  the  inner  nose,  or  that  part  of  the  system  that  selects 
food  by  the  sense  of  smell.      The  sensory  part  of  this  is  in  great  part  from  the 
fifth  nerve,  through  Meckel's  ganglion.     The  special  sense  of  smell  is  from  the 
olfactory  or  first  cranial  nerve. 

6.  Nerve-supply  concerned    in   deglutition.      Here  a    separate    system,  the 
digestive,  begins,  as  is  evidenced  by  a  radical  change  in  the  nerve-supply.     The 
muscles  of  the  soft  palate  and  pharynx  are  supplied  by  the  pharyngeal  plexus, 
the   principal   factors   in  which    are   the   sympathetic   and  vagus   nerves ;    these 
nerves  supply  all  the  other  organs  of  the  digestive  tract. 

What  is  the  salivary  system  ? 

This  system  consists  of  the  salivary  glands,  the  parotid,  the  submaxillary, 
the  sublingual,  and  their  capsules,  their  nerve-supply,  principally  sympathetic, 
and  their  blood-supply.  The  latter  is  derived  from  the  main  artery  of  the 
region  in  which  the  glands  are  found. 

THE  SOFT  PALATE. 

1.  Prevents  rcgurgitation  of  food  into  the  mouth.      (Fig.  64.) 

2.  Prevents  passage  of  ingesta  into  the  posterior  nares. 
The  structures  concerned  are  the  following  : 

1.  The  palato-glossus  muscle.      Nerve-supply,  pharyngeal  plexus. 

2.  The  palato-pharyngeus  muscle.     Nerve-supply,  pharyngeal  plexus. 

3.  The  levator  palati  muscle.      Nerve-supply,  pharyngeal  plexus. 

4.  The  tensor  palati  muscle.     Nerve-supply,  otic  ganglion. 

5.  The  azygos  uvulae.     Nerve-supply,  pharyngeal  plexus. 

To  see  the  action  of  the  palato-glossus  muscle  on  the  living  subject,  make 
prolonged  effort  to  depress  the  tongue.  When  the  patient  is  on  the  verge  ot 
nausea,  you  will  see  the  anterior  pillars  of  the  fauces  spread  out  and  draw  the 
tongue  closely  under  the  palatine  arch.  This  is,  then,  their  action  :  during 
swallowing,  after  the  bolus  passes  the  initial  part  of  the  faucial  passage,  the 
tongue  is  forced  under  this  arch  to  prevent  regurgitation,  while  the  constrictors 
of  the  pharynx  are  contracting  on  the  food.  During  the  same  act  the  palato- 
pharyngei  spread  in  such  a  way  as  to  protect  the  upper  pharynx  and  posterior 
nares,  acting  with  the  levator  palati ;  the  circumflexus  tightens  the  soft  palate. 

The  levator  palati  (Fig.  65)  arises  from  the  cartilage  of  the  Eustachian  tube, 
and  from  the  under  surface  of  the  petrous  portion  of  the  temporal  bone.  It  is 
inserted  into  the  soft  palate  near  the  mid-line. 

The  circumflexus  (Fig.  65),  or  tensor  palati,  arises  from  the  scaphoid  fossa 
of  the  sphenoid  bone.  (Fig.  i  i.)  The  tendon  passes  around  the  hamular  pro- 
cess of  the  internal  pterygoid  plate  and  is  inserted  into  the  median  rap  he  of  the 
soli  palate.  Some  of  its  fibres  are  also  inserted  into  the  posterior  margin  of  the 
hard  palate. 

The   azygos   uvulae  (Fig.  65)  consists  of  some  muscular  fibres  extending 
from  the  posterior  nasal  spine  to  the  end  of  the  a/ygos  uvulae.      (Fig.  1 1.) 


THE   HI'. AH  AND   NECK. 


99 


//6>7t.'  is  the  pharyngecU  plexus  formed  and  wJiat  docs  it  supply  f 

Tliis  plexus  is  formed   by  the  union  of  branches  from — 

1.  The  superior  cervical  ganglion  of  the  sympathetic. 

2.  The  glosso-pharyngeal  nerve,  the  ninth  cranial  nerve. 

3.  The  pneumogastric  or  vagus  nerve,  the  tenth  cranial  nerve. 

4.  The  superior  laryngeal  nerve,  a  branch  of  the  vagus. 

This  plexus  supplies  the  mucous  membrane  and  muscles  of  the  pharynx  and 
all  the  muscles  of  the  soft  palate  except  the  tensor  palati,  which  receives  its 
nerve-supply  from  the  otic  ganglion. 

The  pharyngeal  plexus  may  be  seen  on  your  dissection  on  the  outer  surface 
of  the  middle  and  inferior  constrictors  of  the  pharynx. 

What  functions  may  be  rationally  attributed  to  the  soft  palate  as  a  ivlwlc  ? 

Its  principal  function  seems  to  be  to  direct  food  to  the  stomach  and  protect 
the  other  cavities  communicating  with  the  pharynx  from  invasion  by  the  food, 
(i)  The  anterior  pillars  of  the  fauces  and  the  tongue  prevent  regurgitation  into 
the  mouth.  (2)  The  posterior  pillars  of  the  fauces  prevent  regurgitation  into 
the  nose  through  the  posterior  nares.  (3)  The  epiglottis  protects  the  larynx. 
(4)  The  levator  palati  forms  a  temporary  roof  over  the  pharynx  during  deglu- 
tition, and  thereby  protects  the  Eustachian  tube.  (5)  The  tensor  palati  opens 
the  Eustachian  tube  during  deglutition. 


THE   PHARYNX. 

This  cavity  is  situated  behind  the  nose,  mouth,  and  larynx.  It  connects  the 
mouth  with  the  oesophagus.  It  is  in  communication  with  : 

1.  The  larynx,  which  is  guarded  by  the  epiglottis. 

2.  The  oesophagus,  its  downward  continuation  to  the  stomach. 

3.  The  tympanum,  through  the  Eustachian  tube. 

4.  The  nose,  by  the  posterior  nares. 

5.  The  mouth,  being  partially  shut  off  by  the  fauces.     The  proper   muscles 
of  the  pharynx  are:  (i)   The  superior  constrictor  pharyngis.      (2)  The  middle 
constrictor  pharyngis.      (3)  The  inferior  constrictor  pharyngis.      (4)  The  stylo- 
pharyngis  muscle.      (5)  The  palato-pharyngeus  muscle. 

The  inferior  constrictor  you  will  find  arising  from  (i)  the  cricoid  cartilage  ; 
(2)  the  oblique  line  of  the  thyroid;  (3)  the  inferior  cornu  of  the  thyroid.  It 
is  inserted  into  the  fibrous  raphe.  (Fig.  62.) 

The  middle  constrictor  arises  from  the  cornua  of  the  hyoid  bone,  and  from 
the  stylo-hyoid  ligament.  (Fig.  62.)  It  is  inserted  into  the  median  raphe,  the 
fibres  being  disposed  as  follows  :  (i)  The  inferior  fibres  extend  downward  and 
are  overlapped  by  the  inferior  constrictor  ;  (2)  the  superior  fibres  extend  upward 
and  overlap  the  superior  constrictor  in  part ;  (3)  the  middle  fibres  extend  hori- 
zontally. (Fig.  62.) 

The  superior  constrictor  muscle  of  the  pharynx  (Fig.  62)  is  pale  and 
thin  in  comparison  with  the  inferior  constrictor.  The  reason  of  this  will  be 
appreciated  when  you  understand  the  mechanism  of  deglutition.  Growth  is  the 
correlative  of  function  :  the  function  of  the  inferior  constrictor  is  vigorous  con- 
traction, hence  its  roborous  fibres  ;  on  the  other  hand,  the  function  of  the  superior 
constrictor  is  a  retaining  bag,  hence  its  predominance  of  connective  over  muscular 
tissue. 

This  muscle  has  the  following  origins,  u;hk:U  a»e  ,\vcl;  sl)<-un>iri  figure.  62  :  (i) 
From  the  internal  pterygoid  plate,  lo»vcr  tluVd,  and  .its  ha.rii'.lar  process;  (2) 


IOO 


PRACTICAL  ANATOMY. 


from  the  pterygo-mandibular  ligament ;  (3)  from  the  posterior  fifth  of  the  mylo- 
hyoid  ridge  (Fig.  9)  ;  (4)  from  the  side  of  the  tongue.  The  muscle  is  inserted 
into  the  pharyngeal  spine  of  the  occipital  bone  and  into  the  median  raphe. 


Stylo-hyoid 


Ligament  urn  pharyngeum 


XI 


Posterior  belly  of 
digastric 


Sterno-mastoid 

Rectus  capitis 
anticus  major 

Etylo-pharyngeus 

Stylo-glossus 

Internal  pterygoid 

SUPERIOR 
CERVICAL 
GANGLION 

Middle  constrictor 

Cummon  carotid 
artery 

Inferior  constrictor 

GANGLION 
THYROIDEUM 
(VARIETY) 

THYROID  GLAND 


Inferior  thyroid 

artery 
Subclavian  artery 


RECURRENT 
LARYNGEAL 
NER  VE 


Internal  carotid' 

artery 

RIGHT 

SYMPATHETIC 

Oceiii  Hal  artery 

Posterior  belly  of 
digastric 


DESCENDENS 
HYI'OGLOSSI 

Common  carotid 
artery 

Sterno-mastoid 


TWIG  OF 
RECURRENT 

LARYNGKAL  TO 

PHARYNGEAL 

PLEXUS 

Thyroid  axis 

INFERIOR 
CERVICAL 

GANGLION 

RECURRENT 
LARYNGEAL 

PLEXUS  GULJE 


RIGHT 
PNEVMOGASTRIC 


Thoracic  aorta 

Crus  of  diaphragm  . 

FlG.    6l. — DlSTRIHUTION    OF    THE    PNEUMOGASTRIC    Xl.KVK,    VI  K\VKI  >    1  ROM    11K1IIND.       (Krause.) 

What  can  you  say  of  tlic  structure  of  tlic  pliaryn.v  f 

It  has  three-  coats  :  ;i  ;,V/Y,VW.V,,  vb.idi  is  continuous  with  the  mucous  membrane 
of  the  cavities-with  which  the  ^haCrya>: communicates  ;  a  muscular  coat,  special- 


THE  HEAD  AND  NECK. 


101 


ized  as  constrictors  and  elevators  of  the  pharynx  to  facilitate  deglutition  ;  a  fibrous 
coat,  the  pharyngeal  aponeurosis,  situated  between  the  mucous  and  muscular 
coats,  for  strength  and  support.  This  is  also  called  the  pharyngeal  aponeurosis. 

Between  what  two  points  docs  the  pharynx  extend  ? 

From  the  base  of  the  skull  to  the  cricoid  cartilage. 

What  is  the  pliaryngeal  tonsil,  and  where  is  it  located  ? 

It  consists  of  a  mass  of  lymphoid  tissue  similar  to  that  found  in  the  tonsil. 
It  is  located  on  the  back  part  of  the  pharynx,  between  the  Eustachian  orifices. 


INTERNAL  PTERYGOID  PLATE 
Superior  constrictor 

Pterygo-mandibular 

ligament 
Stylo-hyoid  ligament 

Middle  constrictor 


Stylo-pharyngeua 


Inferior  constrictor 


Thyroid  cartilage 


Crioo-thyroid 
Crieoid  cartilage 


FIG.  62. — THE  MUSCLES  OF  THE  PHARYNX. 


Distinguish  between  pJiaryngeal  fascia  and  pharyngeal  aponeurosis. 

The  fascia  is  behind  the  pharynx.  It  is  the  fourth  layer  of  deep  cervical 
fascia  continued  upward.  The  aponeurosis  is  one  of  the  proper  coats  of  the 
pharynx,  located  between  the  mucous  and  the  muscular  coats. 

What  important  structures  do  yon  find  between  the  superior  and  middle  constric- 
tors of  the  pharynx  ? 

The  glosso-pharyngeal  nerve  and  the  stylo-pharyngeal  muscle.      (Fig.  63.) 

What  do  you  find  between  the  middle  and  inferior  constrictors  of  the  pharynx  ? 

The  superior  laryngeal  branch  of  the  pneumogastric  nerve,  and  the  superior 
laryngeal  branch  of  the  superior  thyroid  artery.  (Fig.  63.) 


102 


PR  A  (.  'TICAL  ANA  TOMY. 


Describe  the  /-'iistac/iia/t  tube. 

It  conveys  air  from  the  pharynx  to  the  middle  ear.  You  may  see  the 
pharyngeal  orifice  on  the  posterior  wall  of  the  pharynx,  in  line  with  the  inferior 
turbinated  bone.  You  will  find  the  tympanic  orifice  in  the  anterior  wall  of  the 
tympanum,  forming  the  lower  of  the  two  compartments  of  the  canalis  musculo- 
tubarius.  This  you  will  understand  when  you  dissect  the  middle  ear  and  the 
petrous  stage  of  the  seventh  nerve.  The  tube  is  an  inch  and  a  half  long  from 
the  posterior  wall  of  the  pharynx  to  the  anterior  wall  of  the  tympanum.  The  tube 


Fn;.  63. — MUSCLES  OF  THE  PHARYNX. 

I.  Orbicularis  oris.  2.  Pterygo-maxillary  ligament.  3.  Mylo-hyoideus.  4.  Os  hyoides.  5.  Thyro- 
hyoicl  ligament.  6.  Pomum  Adami.  7.  Cricoid  cartilage.  8.  Trachea.  9.  Tensor  palati.  10.  Levator 
palati.  II.  Glosso-pharyngeal  nerve.  12.  Stylo-pharyngeus.  13.  Superior  laryn<*eal  nerve  and 
artery.  14.  External  laryngeal  nerve.  15.  Crico  thyroideus.  16.  Inferior  laryngeal  nerve.  17. 
Esophagus. 

has  a  bony  part  in  the  petrous  portion  of  the  temporal  bone  one-half  of  an  inch 
long  ;  it  has  a  fibro-cartilaginous  part  one  inch  long. 

Has  the  cartilaginous  tube  any  practical  importance  as  a  guide  in  dissection  f 

Yes  ;  it  projects  between  the  origins  of  the  levator  palati  and  tensor  palati. 

Give  the  origins  of  t/ic  levator  palati  and  tlie  tensor  palati,  and  show  their  re- 
lation to  tlic  I'.iistac/iian  tube. 

(i)  The  levator  palati  (Fig.  1 1)  arises  from  the  petrous  part  of  the  temporal 
bone  and  from  the  lower  margin  of  the  Kustachian  tube.  This  muscle  you 
find,  then,  behind  the  tube  in  dissecting,  to  the  inner  side.  The  tensor  palati 
(Fig.  1 1 )  arises  from  the  spine  of  the  greater  ala  of  the  sphenoid,  from  the 
scaphoid  fossa,  and  from  the  cartilage  of  the  F.ustachian  tube,  and  is  in  relation 


THE  HEAD  AND  NECK. 


103 


with  the  external  surface  of  the  internal  pterygoid  plate  internally,  and  with  the 
internal  pterygoid  muscle  externally ;  the  tendon  turns  inward  around  the 
hamular  process,  and  is  inserted  into  the  aponeurosis  of  the  soft  palate  and  into 
the  under  surface  of  the  horizontal  plate  of  the  palate  bone.  This  muscle  you 
will  find  in  front  of  and  to  the  outer  side  of  the  cartilaginous  part  of  the 
Eustachian  tube. 

Wliat  is  tlic  salpingo-pJiaryngcus  muscle  ? 

A  name  by  which  those  fibres  of  the  palato-pharyngeus  muscle  are  desig- 
nated that  arise  from  the  cartilaginous  part  of  the  Eustachian  tube. 

Name  all  the  muscles  attached  to  the  Eustachian  tube. 

(i)  The  levator  palati  ;  (2)  the  tensor  palati  ;  (3)  the  salpingo-pharyngeus, 
or  the  Eustachian  part  of  the  palato-pharyngeus  ;  (4)  the  tensor  tympani. 


FIG.  64. — MEDIAN  SECTION  OK  MOUTH,  PHARYNX,  AND  LARYNX. 

Left  nostril.  2.  Upper  lateral  cartilage.  3.  Inner  portion  of  lower  cartilage.  4.  Superior  turbinated 
bone  and  meatus.  5.  Middle  turbinated  bone  and  meatus.  6.  Inferior  turbinated  bone  and  meatus. 
7.  Sphenoid  sinus.  8.  Posterior  nasal  fossa.  9.  Internal  orifice  or  pavilion  of  Eustachian  tube. 
10.  Velum  palati.  II,  II.  Vestibule  of  mouth.  12.  Palatine  vault.  13.  Genio-glossus  muscle. 
14.  Genio-hyoid.  15.  Mylo-hyoid.  16.  Anterior  pillar  of  velum  palati.  17.  Posterior  pillar.  18. 
Tonsil.  19.  Circum  vail  ate  papillse  of  tongue.  20.  Cavity  of  larynx.  21.  Ventricle.  22.  Epiglottis. 
23.  Ilyoid  bone.  24.  Thyroid  cartilage.  25.  Thyro-hyoid  membrane.  26.  Posterior  portion  of 
cricoid  cartilage.  27.  Anterior  portion.  28.  Crico-thyroid  membrane. 


Ho  a'  is  the  pharynx  innervated  ? 

From  the  pharyngeal  plexus,  located  on  the  outer  surface  of  the  middle  and 
inferior  constrictor  muscles  and  formed  by  the  vagus,  glosso-pharyngeal,  and 
by  branches  from  the  superior  cervical  ganglion  of  the  sympathetic. 

Give  the  attachments  of  the  pharynx. 

The  sphenoid  (Eig.  11),  the  pharyngeal  spine  of  the  occipital,  the  petrous 
portion  of  the  temporal,  the  Eustachian  tube,  internal  pterygoid  plate,  posterior 
nares,  mouth  and  larynx,  prevertebral  fascia,  and  oesophagus. 

The  rectus  capitis  anticus  major  arises  from  the  anterior  tubercles  of  the 
transverse  processes  of  the  third,  fourth,  fifth,  and  sixth  cervical  vertebrae.  It  is 
inserted  into  the  under  surface  of  the  basi-occipital  part  of  the  occipital  bone. 


104  PRACTICAL  ANATOMY. 

The   muscle   flexes  the   head.     Its  nerve-supply  is  from   the   first  and  second 
cervical. 

The  rectus  capitis  anticus  minor,  a  small  muscle,  arises  from  the  upper 
part  of  the   lateral  mass   in  front  of  the  articular  process   of  the   atlas.     It  is 


Fharyngeal 
apoueurosis 


Levator  palati 


Tensor  palati 


Azygos  uvulae 
Hamular  process 


TONGUE 


EUSTACHIAN  TUBE 
Levator  palati 


Palato-pharyngeus 


—  Superior  constrictor 


Crico-arytenoideu 
posticua 


EPIGLOTTIS 


Thyroid  cartilage 


Cricoic"  cartilage 


TRACHEA 


ISOPHAGUS 


FIG.  65. — VIKW  OF  MUSCLES  OF  SOFT  PALATE,  AS  SKEN  FROM  WITHIN  THE  PHARYNX. 

(Modified  from  Bourgcry.) 


inserted  into  the  basilar  process  of  the  occipital  bone,  posterior  to  the  preceding 
muscle.     The  muscle  acts  synergistically  with  the  rectus  capitis  anticus  major. 

The  rectus  capitis  lateralis  arises  from  the  lateral  mass  of  the  atlas.  It  is 
inserted  into  the  jugular  process  of  the  occipital  bone.  Its  action  is  to  flex  the 
head  laterally.  This  and  the  preceding  muscle  are  supplied  by  the  first  cervical 
nerve. 


THE   HEAD   AND   NECK. 


The  longus  colli. 

Origin. — i.    From  bodies  of  sixth  and  seventh  cervical  and  first,  second, 

and  third  dorsal. 

Insertion. — 2.   Into  the   bodies    of  the  second,    third,  and  fourth    cer- 
vical. 

w   (  Origin. —  I.   Anterior  tubercles  of  transverse  processes  of  third,  fourth, 

and  fifth  cervical. 
"   I  Insertion. — 2.  Tubercle  on  anterior  arch  of  the  atlas. 


Rsetus  capitis  lateralis 


Rectus  capitis  anticus 
major 


Origin  of  rectus  capitis 
anticus  major 


Scalenus  medius 


Scalenus  antlous 


Scalenua  posticus 


Rectus  capitis  later- 
alis 

Rectus  capitis  anti- 
cus minor 


Intertransyersalis 
anterior 


Intertransversalis 
posterior 


Longus  colli 


Insertion  of  scalenus 
anticus 


Scalenus  medius 


Scalenus  posticus 


FIG.  66. — THK  MUSCLES  OF  THE  FRONT  OF  THE  NECK. 


'*  S   f  Origin. —  i.    Bodies  of  first,  second,  and  third  dorsal  vertebrae. 
.  £  2*  <  Insertion. — 2.   Anterior  tubercles   of  transverse  processes  of  fifth  and 

C   iJ      I  .  , 

JQ  i.  sixth  cervical. 

These  muscles  are  supplied  by  the  anterior  divisions  of  the  cervical   nerves. 
The  action  is  evident :  flexion  direct,  lateral,  or  combined  in  rotation. 


io6 


PRACTICAL  ANA  TOM}. 


THE   LARYNX. 

The  upper  part  of  the  respiratory  tract  is  called  the  larynx.  Its  downward 
continuation  into  the  neck  and  thorax  is  the  trachea.  The  essential  organ  of 
voice  is  a  vocal  cord  on  each  side  of  a  chink  called  the  rima  glottidis.  The 
greater  part  of  the  larynx  is  set  aside  as  a  protective  for  the  delicate  vocal  cords. 


BODY  OF  HYOID  BONE 
Thyro-hyoid  ligament 

Cartilage  triticea 
Foramen  for  superior 

laryngeal  nerve 
Median  portion  of  thyro- 

hyoid  membrane 

SUPERIOR  CORNU  OF  THYROID 

CARTILAGE 

MEDIAN  NOTCH  OF  THYROID 
CARTILAGE 

Fomum  Adami 


OBLIQUE  LINE  OF  THYROID 
CARTILAGE 


Crico-thyroid  membrane 


INFERIOR  CORNU  OF  THYROID 
CARTILAGE 


THIRD  RING  OF  TRACHEA 


OBLIQUE  LINE  BELOW  SUPERIOR 

TUBERCLE 
WING  OF  CARTILAGE  BEHIND 

OBLIQUE  LINE 

OBLIQUE  LINE  ABOVE  INFERIOR 
TUBERCLE 

ANTERIOR  BORDER  OF  INFERIOR 
CORNU 


FIG.  67. — FRONT  VIEW  OF  THE  CARTILAGES  OK  THE  LARYNX.     (Modified  from  Bourgery  and  Jacob.) 


POSTERIOR  SURFACE  OF  ARYTENOID 


MUSCULAR  EXTERNAL  ANGLE 
Crioo-arytenoid  joint 


POSTERIOR  SURFACE  OF  CRICOID 
CARTILAGE 


Longitudinal  fibres  of  oesophagus 


CORNICULUM   LARYNCIS 


Arytenoideus  muscle 


Crieo-arytenoideus  posticus  muscle 


Crioo-arytenoideus  posticus  muscle 


ARTICULAR  SURFACE  FOR  INFERIOR  CORNU 
OF  THYROID  CARTILAGE 


FIG.  68. — BACK  VIEW  OF   THE  CRICOID  AND  AKYTKNOID   CARTII.ACKS.     (Modified   from   Bourgery 

and  Jacob.) 

A  minor  part  of  the  larynx  is  set  aside  to  move  the  vocal  cords.  To  gain  a 
comprehensive  idea  of  the  larynx  in  your  dissection,  you  must  find  on  your 
dissection  the  following  structures  : 

1.  The  thyroid  cartilage  and  hyoid  bone.     (Fig.  67.) 

2.  The  thyro-hyoid  membrane  and  median  notch  of  thyroid  cartilage. 


THE  HEAD  AND  NECK. 


107 


3.  The  cricoid  cartilage  and  crico-thyroid  membrane.      (Fig.  67.) 

4.  The  arytenoid  cartilages  surmounting  the  cricoid  cartilages. 

5.  The  epiglottis  in  the  retiring  angle  of  the  thyroid  cartilage.      (Fig.  69.) 

6.  The  mucous  membrane  of  the  larynx. 

7.  The  superior  laryngeal  nerve  of  the  vagus  nerve.      (Figs.  63  and  71.) 

8.  The  inferior  laryngeal   nerve   (the  recurrent  branch — figure   71)  of  the 


vaeus. 


GREATER  CORNU  OF  HYOID 

BONE 
BODY  OF  HYOID  BONE 


Thyro-hyoid  ligament 

EPIGLOTTIS 


Median  notch 

Origin  of  thyro-epiglottic 

ligament 
POSTERIOR  EDGE  OF  THYROID 

CARTILAGE 

Origin  of  thyro-aryte- 
noideus  muscle 


INFERIOR  CORNU 


SMALLER  CORNU  OF  HYOID 
BONE 


CARTILAGO  TRITICEA 


SUPERIOR  CORNU  OF  THYROID 
CARTILAGE 


RIGHT  ALA  OF  THYROID 
CARTILAGE 


False  vocal  cord 
True  vocal  cord 


Origin  of  thyro-epiglot- 
tideus  muscle 


FIG.  69. — POSTERIOR  VIEW  OF  THYROID  CARTILAGE  WITH  EPIGLOTTIS. 

9.   The  superior  laryngeal  artery,  a  branch  of  the  superior  thyroid  artery. 
(Fig.  28.) 

10.  The  sympathetic  nerve  with  the  laryngeal  arteries. 

1 1.  The  inferior  laryngeal  artery,  a  branch  of  the  inferior  thyroid.      (Fig.  28.) 

1 2.  The  vocal  cords — true  and  false. 

13.  The  ventricle,  the  space  between  true  and  false  cords. 


Thyro-arytenoideus  muscle 


Attachment  of  erico-thyroid  muscle 


ANTERIOR  SURFACE  OF  ARYTENOID  CARTILAGE 


Cut  edge  of  eapsular  ligament 
Lateral  crico-arytenoid  muscle 


MUSCULAR  EXTERNAL  ANGLE  OF  ARYTENOID 
CARTILAGE 


Lateral  crico-aryteuoid  muscle 
CRICOID  CARTILAGE 


FIG.  70. — FRONT  VIEW  OF  THE  CRICOID  AND  ARYTENOID  CARTILAGES. 

and  Jacob.) 


(Modified    from    Bourgery 


14.  The  intrinsic  muscles  of  the  larynx. 

15.  The  relation  of  the  epiglottis  to  the  tongue. 

The  thyroid  cartilage  (Fig.  67)  has  two  alae  united  in  the  mid-thyroid  line. 
The  result  of  this  union  gives  us  the  pomum  Adami  in  front,  and  the  retiring  or 
receding  angle  of  the  thyroid  cartilage  behind.  (Fig.  69.)  The  former  is  a 
guide  in  surgical  operations  on  the  larynx  and  trachea  ;  the  latter  is  of  great  im- 
portance in  learning  the  anatpmy  and  physiology  of  the  vocal  cords.  Along  the 


io8 


PRACTICAL  ANATOMY. 


superior  border  of  the  thyroid  cartilage,  in  the  mid-line,  you  will  see  the  thyroid 
median  notch.  Each  thyroid  ala  has  a  superior  cornu  and  an  inferior  cornu. 
The  inferior  cornu  articulates  with  the  cricoid  cartilage,  forming  the  crico-thyroid 
articulation.  (Fig.  67.)  The  superior  cornu  gives  attachment  to  the  lateral 
thyro-hyoid  ligament.  The  outer  surface  of  the  ala  has  an  oblique  line,  limited 
above  and  below  by  a  superior  and  inferior  tubercle  respectively.  (Fig.  67.) 

The  retiring  angle  of  the  thyroid  cartilage  (Fig.  69)  gives  origin  to:  (i) 
The  epiglottis  ;  (2)  the  false  vocal  cords  ;  (3)  the  true  vocal  cords  ;  (4)  the 
thyro-arytenoid  muscle  ;  (5)  the  thyro-epiglottideus  muscle. 

The  cricoid  cartilage  (Figs.  68  and  70)  forms,  as  you  will  see,  a  complete 
ring.  It  is  very  narrow  in  front ;  quite  wide  behind.  The  arytenoid  cartilages 


GREATER  CORNU  OF 

HYOID  BONE 
CARTILAOO  TRITICEA 


SUPERIOR      CORNU      OF 
THYROID  CARTILAGE 


BRANCH  TO  LATERAL 
CRICO  •  ARYTENOID 
AND  TBYRO-ARYTE- 
.VOID  MUSCLES 
BKANCB  JOINING  THE 
SUPERIOR       LARYN- 
GEALKERVR 
Crico-arytenoldeu* 
posticus  muscle 
INFERIOR    CORNU    OF 
THYROID  CARTILAGE 


FORAMEN  C/EOUM 
BASE  OF  TONGUE 


EXTERNAL  LARYN- 
GJKAL  NERVE 

INTERN  A  L  LA  R  YN- 
<;I:AL  NERVE 

Cut  edge  of  thyro- 
hyoid  membrane 


AryteuoideuB  muacle 


RECURRENT 
LARYNOEAL 
NER  VJ£ 


FIG.  71. — NERVES  OF  THE  LARYNX.     (Posterior  view.) 


rest  upon  the  superior  border  of  the  cricoid,  behind,  forming  a  movable  articula- 
tion, called  the  crico-arylenoid. 

The  arytenoids  are  small.     You  must  learn  the  following  geometrical  de- 
scription of  the  arytenoids  before  you  can  dissect  the  larynx  understandingly, 
much  less  understand  the  action  of  the  arytenoids  : 
Apex,  obtruncate  and  points  backward  and  inward. 
Base,  articulates  with  the  cricoid  cartilage.     (Fig.  68.) 
Posterior  surface  is  occupied  by  the  arytenoicleus  muscle.     (Fig.  68.) 
Anterior  surface  for  attachment  of  false  cords  and  thyro-arytenoideus.     (Fig. 

/o.) 

Internal  surface  is  covered  by  mucous  membrane. 

Anterior  angle,  processus  vocalis  for  insertion  of  true  vocal  cord.    (Fig.  68.) 


THE   HEAD   AND   NECK. 


109 


External  angle  for  insertion  of  posterior  and  lateral  crico-arytenoid  muscles. 
The  intrinsic  muscles  are  as  follows  : 

1.  The  thyro-arytenoideus.      (Fig.  70.) 

2.  The  crico-arytenoideus  lateralis.      (Fig.  70.) 

3.  The  crico-arytenoideus  posticus.      (Fig.  69.) 

4.  The  arytenoideus.     (Fig.  69.) 

5.  The  crico-thyroid.     (Fig.  27.) 

The  intrinsic  muscles  and  the  mucous  membrane  are  supplied  by  (i)  the 
superior  laryngcal  branch  of  the  pneumogastric ;  (2)  the  inferior  laryngeal 
branch  of  the  pneumogastric  ;  (3)  the  sympathetic  nerves  accompanying  the 
superior  and  inferior  laryngeal  arteries  ;  they  take  the  name  of  the  arteries. 

The  superior  laryngeal  nerve  (Fig.  71)  supplies  the  mucous  membrane  and 
the  crico-thyroid  muscle. 


Epiglottis 


Cut  edge  of  hyo-epiglottidean 

ligament 

SECTION  THROUGH  BODY  OF  HYOID 
BONE 

Peri  glottis 

Cut  edge  of  thyro-hyoid 
membrane 

Thyro-epiglottideus  muscle 


SECTION  OF  THYROID  CARTILAGE 
Thyro-arytenoideuB  muscle 


Crioo  -  arytenoideua  lateralis 
muscle  (the  pointer  crosses 
erieo-thyroid  membrane) 

CRICOID  CARTILAGE 


Aryteno-epiglottidean  fold 
Aryteno-epiglottideus  muscle 


Arytenoideus  muscle 


Crleo-arytenoideus  postious 


Recurrent  laryngeal  nerve 


FIG.  72. — SIDE  VIEW  OF  THE  MUSCLES  AND  LIGAMENTS  OF  THE  LARYNX. 

The  inferior  laryngeal  supplies  the  remaining  muscles. 

The  false  vocal  cord  extends  from  the  retiring  angle  of  the  thyroid  cartilage 
(Fig.  69)  to  the  anterior  surface  of  the  arytenoid  cartilage.  (Fig.  70.) 

The  true  vocal  cord  extends  from  the  retiring  angle  of  the  thyroid  cartilage 
(Fig.  69)  to  the  anterior  angle  of  the  arytenoid  cartilage.  (Fig.  70.) 

The  chink,  or  rima  glottidis,  is  the  space  between  the  two  true  vocal  cords. 
This  chink  consists  of  two  parts — a  respiratory  or  posterior  and  a  vocalizing  or 
anterior. 

The  thyro-arytenoid  muscle  (Fig.  69)  extends  from  the  retiring  angle  of 
the  thyroid  cartilage  to  the  anterior  surface  of  the  arytenoid  cartilage.  (Fig.  70.) 
The  action  of  this  muscle  is  to  pull  the  arytenoid  cartilage  forward  and  thereby 
relax  the  vocal  cords. 

The  arytenoid  muscle  (Fig.  71)  extends  from  the  posterior  surface  of  one 


no  PRACTICAL   ANATOMY. 

to  that  of  the  other  arytenoid  cartilage.      It  approximates  the  vocal  cords  by 
drawing  the  arytenoids  together. 

The  crico-arytenoideus  lateralis  (Fig.  72)  arises  from  the  upper  border 
of  the  side  of  the  cricoid  cartilage.  It  is  inserted  into  the  external  angle  of  the 
base  of  the  arytenoid  cartilage.  The  action  is  to  draw  the  vocal  cords  together 
and  close  the  glottis. 

The  crico-arytenoideus  posticus  arises  on  the  posterior  part  of  the  cricoid. 
It  is  inserted  into  the  outer  angle  of  the  base  of  the  arytenoid  cartilage.  This 
muscle  draws  the  vocal  cords  apart,  and  thereby  opens  the  glottis. 

The  crico-thyroid  muscle  arises  from  the  side  of  the  cricoid  cartilage.  It 
is  inserted  into  the  lower  corner  of  the  thyroid  cartilage.  It  tightens  the  vocal 
cords. 

Describe  the  superior  laryngeal  nerve.     (Fig.  71.) 

It  is  a  branch  of  the  ganglion  of  the  trunk  of  the  pneumogastric  nerve.  It 
passes  behind  the  internal  and  external  carotid  arteries.  It  is  joined  by  com- 
municating branches  from  the  sympathetic  nerve  and  the  pharyngeal  plexus.  It 
divides  into  an  internal  and  an  external  branch.  The  external  branch  pierces  the 
inferior  constrictor  of  the  pharynx  near  the  lower  border  of  the  thyroid  cartilage 
(Fig.  63),  and  is  distributed  principally  to  the  crico-thyroid  muscle  ;  some  few 
filaments  are  distributed  to  the  mucous  membrane.  The  internal  division,  in 
company  with  the  superior  laryngeal  artery,  passes  under  the  thyro-hyoid 
muscle  (Figs.  27  and  71),  pierces  the  thyro-hyoid  membrane,  and  is  distributed 
to  the  mucous  membrane,  communicating  here  with  the  recurrent  laryngeal 
nerve.  (Fig.  71.) 

Describe  the  course  of  the  recurrent  laryngeal  nerves.     (Fig.  71.) 

The  nerve  of  the  right  side  is  given  off  from  the  pneumogastric  in  front  of 
the  first  stage  of  the  subclavian  artery.  It  passes  upward,  under,  and  behind 
the  subclavian  artery,  then  behind  the  common  carotid  to  the  side  of  the  trachea. 
It  lies  in  a  fatty  groove  between  the  trachea  and  oesophagus,  and,  in  company 
with  the  inferior  laryngeal  artery,  passes  upward,  under  the  inferior  constrictor 
of  the  pharynx,  to  the  larynx.  It  is  distributed  to  all  the  intrinsic  muscles  of 
the  larynx  except  the  crico-thyroid.  The  recurrent  laryngeal  nerve  of  the  left 
side  is  given  off  from  the  pneumogastric  in  front  of  the  transverse  part  of  the 
aortic  arch,  passes  under  this  vessel  behind  the  obliterated  ductus  arteriosus,  and 
gains  the  fatty  space  between  the  trachea  and  oesophagus,  and  has  the  same  sub- 
sequent course  and  distribution  as  the  nerve  on  the  right  side.  In  their  course 
between  the  oesophagus  and  trachea  these  nerves  give  off  branches  to  these 
conduits. 

Describe  the  blood-supply  of  the  larynx.     (Fig.  28.) 

The  superior  laryngeal  artery  is  a  branch  of  the  superior  thyroid.  It  accom- 
panies the  superior  laryngeal  nerve,  piercing  with  this  nerve  the  thyro-hyoid 
membrane.  The  inferior  laryngeal  artery  is  a  branch  of  the  inferior  thyroid.  It 
passes  behind  the  inferior  constrictor  of  the  pharynx  with  its  accompanying 
nerves. 

Describe  the  trachea. 

It  is  an  air  conduit,  extending  from  the  larynx  to  the  tracheal  bifurcation, 
where  the  bronchial  tubes  begin.  Compared  to  the  vertebral  column,  in  front  of 
which  the  trachea  lies,  it  extends  from  the  fifth  cervical  to  the  fifth  thoracic  verte- 
bra. It  is  one  inch  in  width  and  five  inches  long. 

The  structure  of 'the  trachea  fits  it  admirably  for  its  specific  double  function 
(i)  of  transmitting  air  inward  and  (2)  of  extruding  both  air  and  accumulated 
mucus,  bearing  crude  inhaled  impurities.  Imperfect  rings  of  cartilage,  held 
together  by  fibro-elastic  membrane  possessing  some  muscular  fibres,  a  rich  nerve- 
ami  blood-supply,  and  a  lining  of  mucous  membrane,  are  the  anatomical  tissues 


THE   HEAD  AND   NECK.  in 

that  specially  qualify  the  trachea  for  its  important  duty.  The  front  part  of  the 
trachea  is  round,  the  back  part  flat.  The  space  between  the  ends  of  the  imper- 
fect rings  of  cartilage  behind  is  filled  by  the  musculus  trachealis.  This  consists 
of  transverse  and  longitudinal  unstriped  fibres.  The  arrangement  of  these  is 
such  as  to  set  up  a  vermicular  movement  in  the  trachea  when  expectoration 
occurs. 

The  nerve-supply  of  the  trachea  comes  from  the  vagus  and  also  from  the 
recurrent  laryngeal,  a  branch  of  the  vagus,  as  this  latter  nerve  lies  in  the  fatty 
groove  between  the  trachea  and  oesophagus ;  and  from  the  sympathetic,  which 
latter  nerves  accompany  the  tracheal  arteries,  and  take  the  same  name. 

The  blood-supply  of  the  trachea  comes  from  the  inferior  thyroid  artery,  a 
branch  of  the  thyroid  axis  of  the  subclavian  artery.  (Fig.  36.)  The  veins  join 
the  thyroid  plexus  of  veins.  Of  the  thyroid  veins,  you  will  remember,  the  right 
opens  into  the  right  innominate,  the  left  into  the  left  innominate  vein.  Each  of 
these  has  valves  where  it  becomes  tributary  to  the  larger  vessel.  These  thyroid 
veins  communicate  on  the  trachea.  These  are  the  troublesome  vessels  in  low 
tracheotomy. 

Relations  of  the  Trachea. — If  you  will  review  your  dissection,  you  will  find  in 
front  of  the  cervical  part  of  the  trachea  the  isthmus  of  the  thyroid  gland  (Fig.  27), 
the  inferior  thyroid  veins,  the  sterno-hyoid  and  sterno-thyroid  muscles  (Fig.  27), 
the  deep  cervical  fascia,  superficial  fascia,  and  skin.  Behind,  the  trachea  is  in  rela- 
tion with  the  oesophagus.  On  each  side  are  the  common  carotid  arteries,  the  infe- 
rior thyroid  artery,  the  recurrent  laryngeal  nerve,  and  the  lobes  of  the  thyroid 
gland.  (Fig.  31.)  The  thoracic  part  of  the  trachea,  as  you  will  see  at  a  later 
stage  of  your  work,  is  covered  by  the  manubrium  sterni,  the  remains  of  the  thymus 
gland,  the  left  brachio-cephalic  vein,  the  aortic  arch,  the  innominate  and  left  com- 
mon carotid  arteries,  and  the  deep  cardiac  plexus.  Posteriorly  is  the  oesophagus, 
and  laterally  the  vagus  nerves  are  on  each  side. 


THE    NASAL   FOSS.E— INTERNAL   NOSE. 

Dissection. — With  a  sharp  saw  cut  through  (i)  the  symphysis  of  the  mandible. 
Then  take  a  sharp  knife  and  cut  through  the  tongue  from  base  to  tip  in  the  mid- 
line,  as  far  forward  and  downward  as  the  hyoid  bone.  (2)  Let  an  assistant  hold 
the  divided  halves  of  the  mandible  apart,  while  you  saw  through  the  mid-line  of 
the  remainder  of  the  face.  (Fig.  64.)  Precaution  :  Before  you  make  the  latter 
cut,  observe  to  which  side  the  septum  nasi  is  deflected  ;  cut  on  the  opposite  side, 
so  as  to  have  the  septum  intact  for  study.  The  cuts  have  placed  before  you  for 
study  the  mouth  and  nasal  fossae.  Very  little  dissection  in  addition  to  that  already 
done  is  necessary. 

The  nasal  fossae  have  the  following  geometrical  parts  : 

1 .  Roof,  formed  by  the  nasal  bones,  the  nasal  spine  of  the  frontal  bone,  crib- 
riform plate  of  the  ethmoid,  the  under  surface  of  the  body  of  the  sphenoid. 

2.  A  floor  (Fig.  74),  formed  by  the  hard  and  soft  palate,  covered  by  mucous 
membrane.     The  hard  palate  is  formed  by  the  palatine  process  of  the  superior 
maxilla  and  the  horizontal  part  of  the  palate  bone. 

3.  An  inner  wall  (Fig.  74),  formed  by  the  septum  nasi,  covered  by  mucous 
membrane.    The  septum  nasi  is  composed  of  (i)  thevomer  ;  (2)  the  vertical  plate 
of  the  ethmoid  ;  (3)  the  cartilaginous  septum — quadrangular  in  some,  triangular 
in  other  cases. 

The  outer  surface  is  formed  by  the  nasal   bones,  the  nasal  process  of  the 


112 


PR  A  CTICAL   ANA  TO  MY. 


superior  maxilla,  the  lachrymal,  ethmoid,  inner  surface  of  superior  maxilla,  in- 
ferior turbinated,  vertical  plate  of  palate  bones,  and  inner  surface   of  pterygoid 


PTERYGO-PALATINE  CANALS 


VIOIAN  CANAL 


PTERYGOIO  FOSSA 
EXTERNAL  PTERYGOID  PLATE 

TUBEROSITY  OF  PALATE  BONE 


FORAMEN  OVALE 


INTERNAL  PTERYGOiD  PLATE 


HAMULAR  PROCESS 


SPINE  OF  PALATE  OR  POSTERIOR 
NASAL  SPINE 

FIG.  73. — THE  POSTERIOR  NARES. 


NASAL  BONE  Frontal  sinus 


Sphenoidal  sinus 


UPPER  LATERAL  CARTILAGE 

Groove  between  septa! 
and  upper  lateral 
cartilage 


LOWER  LATERAL 


THICKENED  BORDER  OF  CARTILAGE  RESTING          i  \  Pouch  at  uprer 

UPON  ANTERIOR  NASAL  SPINE          Incisive  papilla      \  extremity  of  Sten- 

SEPTAL  CARTILAGE  8on'8  canal 


ORIFICE  OF  EUSTACHiAN 

TUBE 
SOFT  PALATE 


FIG.  74. — SECTION  SHOWING  BONY  AND  (.'AIM -11  .ACINOI  s  SKITCM. 
The  dotted  line  indicates  the  course  of  the  anterior  palatine  canal. 

process  of  the  sphenoid  bone.      This  surface  is  covered  by  mucous  membranr. 
This  must  be  studied  on  the  dry  skull. 

The  anterior  narcs  is  the  inlet  to  the  nose  from  the  external  world.     The 


THE   HEAD   AND   NECK. 


IT3 


posterior  nares  is  the  opening  into  the  pharynx.  (Fig.  73.)  Notice:  On  the 
outer  wall,  and  even  forming  part  of  the  same,  are  the  three  turbinated  bones. 

Study  figure  74.  Remove  the  mucous  membrane  from  the  septum,  and  find 
(i)  suture  between  the  vomer  and  ethmoid  ;  (2)  junction  between  cartilage  and 
ethmoid  ;  (3)  the  naso-palatinc  groove  on  the  vomer,  containing  a  nerve  and  an 
artery  of  the  same  name.  The  nerve,  a  branch  of  Meckel's  ganglion,  one  on  each 
side,  passes  through  the  foramina  of  Scarpa,  in  the  anterior  palatine  canal  (Fig. 
74),  and  anastomoses  with  the  anterior  palatine  nerves,  also  branches  of  Meckel's 
ganglion.  (Figs.  53  and  75.) 

The  turbinated  bones  (Fig.  77)  are  three  in  number.  They  occupy  the  outer 
wall,  as  follows  fractionally  :  The  superior  turbinal,  the  posterior  third  ;  the  middle 
turbinated,  the  posterior  two-thirds  ;  the  inferior  turbinated  extends  the  whole 
length  of  the  wall. 


NA  SA  L     OLFA  CTOR  Y 
FRONTAL  SINUS  NERVE          NERVE 


OLFACTORY  NERVE 
TO  SUPERIOR  TL'R- 
JilNA  TE  BONE 

SPHENOIDAL  SINUS 


VIDIAN  NERVE 

MECKEL'S 

GANGLION 
DESCENDING 

PALATINE 

ORIFICE  OF  EUSTACHIAN 
TUBE 

NASAL  BRANCHES 


POSTERIOR 

PALATINE 
ANTERIOR 

PA  LA  TINE 
MIDDLE  PALATINE 


FIG.  75. — NERVES  OF  THE  NASAL  CAVITY. 

Tlie  Etluno-turbinals  (Fig.  77). — This  name  is  given  to  the  superior  and  middle 
turbinals.  They  belong  to  the  lateral  mass  of  the  ethmoid  bone. 

The  meatuses  are  three  irregular  cavities  on  the  outer  wall  of  the  nasal 
fossae.  Into  them  open  the  nasal  duct  and  the  frontal,  ethmoidal,  maxillary,  and 
sphenoidal  sinuses  : 

Inferior,  receives  the  nasal  duct  conveying  the  tears. 

Middle,  receives  the  openings — the  antrum,  frontal,  and  anterior  ethmoidal  cells. 

Superior,  the  opening  of  the  sphenoidal  and  posterior  ethmoidal  cells. 

Describe  the  nasal  mucous  membrane. 

It  is  called  pituitary  membrane,  from  an  erroneous  idea  entertained  by  the 
ancients  that  the  nasal  deflections  had  their  origin  in  the  pituitary  body.  It  is 
also  called  the  Schneiderian  mucous  membrane.  In  the  regions  of  the  turbinals 
and  septum  it  is  thick,  vascular,  and  loosely  attached  to  the  bone  ;  in  the  bottom 
of  the  meatuses  and  in  the  intramural  sinuses  communicating  with  the  nasal 


H4  PRACTICAL   ANATOMY. 

fossae  it  is  thin.      It  is  continuous  with  the  mucous  membrane  of  all  the  cavities 
with  the  nasal  fossae  communicante. 

Name  the  arteries  that  supply  the  nasal  fossa. 

1.  The  anterior  and  posterior  ethmoidal  supply  the   roof,  outer  wall,  and 
upper  half  of  the  septum.     These  are  branches  of  the  ophthalmic,  and  leave  the 
orbital  cavity  by  the  anterior  and  posterior  ethmoidal  foramina.     The  companion 
veins  have  like  name,  and  are  tributary  to  the  ophthalmic  vein.     Infection  in  this 
region,  then,  might  extend  along  the  ophthalmic  vein  to  the  cavernous  sinus, 
since  this  vein  has  no  valves. 

2.  The  spheno-palatine  supplies  the  lower  half  of  the  septum,  the  turbinals, 
the  meatuses,  the  frontal  sinuses,  and  the  antra.     The  companion  veins  of  these 
arteries  are  confluent  to  the  pterygoid  plexus  on  the  inner  side  of  the  internal 
pterygoid  muscle  ;  the  veins  take  the  same  name  as  the  arteries.     The  pterygoid 


Frontal  sinusec 


MIDDLE  TURBINAL 
BONE 

NASAL  SEPTUM 


RIGHT  ANTRUM 


INFERIOR  TURBINAL 
BONE 


FIG.  76. — TRANSVERSE  SECTION  PASSING  THROUGH  THE  NASAL  Foss^:  AND  ANTRA  AT  THE 
POSTERIOR  EXTREMITY  OF  THE  MIDDLE  TURBINAL  BONE.     (Seen  from  the  front.) 

plexus  communicates  with  the  cavernous  sinus  by  the  Vesalian  vein.  Infection 
from  this  region  may  reach  the  sinus,  since  the  Vesalian  has  no  valves. 

3.  The  descending  palatine  and  Vidian  arteries,  branches  of  the  internal  max- 
illary, supply  the  nasal  fossae. 

What  can  you  say  of  the  nasal  mucous  membrane  in  relation  to  nose  bleeding , 
and  in  what  way  may  a  violent  hemorrhage  from  the  nose  abort  cerebral  apoplexy  ? 

The  venous  blood  in  the  mucous  membrane  of  the  nose  communicates  with 
the  superior  longitudinal  sinus,  in  the  falx  cerebri,  by  an  emissary  vein  which 
passes  through  the  foramen  caecum  in  front  of  the  crista  galli.  The  nasal  mucous 
membrane  is  very  vascular  and  quite  loosely  attached,  a  condition  favoring  easy 
rupture  of  its  vessels.  In  cerebral  congestion  of  the  face  the  ocular  and  nasal 
mucous  membranes  become  engorged,  on  account  of  their  communication  with 
the  sinuses.  On  account  of  its  lax  attachment  the  vessels  of  the  nasal  mucous 


THE  HEAD  AND  NECK.  115 

membrane  frequently  give  way,  and  hemorrhage  results.      This  occurs  more  fre- 
quently in  children  than  in  adults. 

Describe  the  nerve-supply  to  the  mucous  membrane  of  the  nose. 

1.  The  olfactory  nerves  are  distributed  to  the  Schneiderian  membrane  of  the 
upper  third  of  the  septum,  and  to  the  superior  and  middle  turbinals. 

2.  The  nasal  nerve,  a  branch  of  the  ophthalmic  division  of  the  fifth  nerve, 
supplies  the  anterior  half  of  the   roof,  outer  wall,  and  inner  wall   of  the  nasal 
fossae  with  common  sensation. 

3.  The  upper  branches  of  Meckel's  ganglion  and  the  Vidian  nerve  supply 
the  posterior  half  of  the  roof,  outer  wall  and  inner  wall,  and  the  superior  tur- 
binal. 

4.  The  anterior  palatine  branch  of  Meckel's  ganglion  on  its  way  down  to  the 
roof  of  the  mouth  supplies  the  middle  and  inferior  turbinals. 


Frontal  sinus 


Orifice  of  middle  ethmoidal  cells 

SUPERIOR  TURBINAL  BONE 
Orifice  of  the  posterior  ethmoidal  cells 
Orifice  of  the  sphenoidal  sinus 
Sphenoidal  sinus 


Orifloe  of  frontal  sinus 


UPPER  ORIFICE  OF 
NASAL  DUCT 


ORIFICE  OF  EUSTAOHIAN 
TUBE 


LOVvER  ORIFICE  OF  NASAL  DUCT 


MIDDLE  TURBINAL  BONE 

INFERIOR  TURBINAL  BONE      ORIFICE  OF  THE  ANTRUM      ORIFICE  OF  INFUNDIBULUM 

FIG.  77. — SECTION  OF  THE  NOSE,  SHOWING  THE  TURBINAL  BONES  AND  MEATUSES, 
WITH  THE  OPENINGS  IN  DOTTED  OUTLINE. 

5.  The  naso-palatine  branch  of  Meckel's  ganglion  supplies  the  lower  and 
posterior  part  of  the  septum.  The  anterior  superior  dental  nerves  supply  the 
inferior  turbinated  bone,  hence  a  disease  of  this  bone  may  cause  pain  in  the  ear 
or  in  any  of  the  teeth. 

The  Intramural  Sinuses. — This  is  a  convenient  term  by  which  to  distinguish 
the  air-containing  cells,  in  connection  with  some  of  the  bones  of  the  skull  and  face, 
from  the  dural  sinuses  in  the  dura  mater,  whose  use  is  to  contain  and  convey  blood 
away  from  the  brain.  These  sinuses  are  the  ethmoid,  the  sphenoidal,  the  mastoid, 
the  maxillary  or  antrum  of  Highmore,  the  frontal,  mastoid  antrum,  and  mastoid 
cells.  As  they  all  communicate  directly  or  indirectly  with  the  nasal  fossae,  we 
will  consider  them  in  this  place.  The  mastoid  cells  communicate  with  the  middle 
ear,  and  this  with  the  pharynx  by  the  Eustachian  tube.  The  others  communi- 
cate with  the  nasal  fossae  as  indicated  in  figure  77. 

Formation. — The  intramural  cells  are  formed  by  absorption  of  the   middle 


n6 


PRACTICAL    ANATOMY. 


or  diploic  plate  of  bone.  They  are  lined  by  mucous  membrane.  Infection  is 
very  liable  to  occur  in  these  sinuses.  The  difference  between  the  mucous  mem- 
brane of  the  sinuses  and  that  of  the  mouth  is  this  :  the  latter  is  more  vascular, 
more  hardy,  more  resisting,  both  to  infection  and  traumatic  causes,  on  account 
of  its  location  being  such  that  exposes  it  to  friction.  Structure  being  the 
correlative  of  function,  an  increased  blood-supply  would  logically  account  for  the 
superior  hardihood  and  less  vulnerable  character  of  the  mucous  membrane  of 
the  mouth,  and  all  other  regions  where  friction  is  a  consideration  inseparable 
from  the  environment. 

Take  special  notice  that — 

1.  The  orifice  of  the  Eustachian  tube  is  on  a   direct  line  with  the   inferior 
meatus. 

2.  A  fine  straw  or  bristle  can  be  passed  through  the  infundibulum  (Fig.  77) 
of  the  frontal  sinus,  into  the  middle  meatus. 

3.  A  straw  can  be  passed  through  the  nasal  duct  into  the  inferior  meatus  ; 
by  turning  the  inferior  turbinated  bone  up,  you  can  easily  see  the  orifice  for  the 
nasal  duct. 

4.  The  inferior  meatus  is  located  between  the  floor  of  the  nasal  fossae  and 
the  inferior  turbinated  bone,  and  receives  the  end  of  the  nasal  duct.      (Fig.  77.) 


ANTRUM 


POSTERIOR  PALATINE  GROOVE 
PALATINE  PROCESS 


NASAL  PROCESS 

RIDGE  FOR  MIDDLE  TURBINAL 

LACHRYMAL  GROOVE 

RIDGE  FOR  INFERIOR  TURBINAL 

NASAL  SPINE 

CREST 

ANTERIOR  PALATINE  GROOVE 


FIG.  78. — THE  LEFT  MANILLA.     (Inner  view.) 

5.  The  middle  meatus  is  situated  between  the  inferior  and  middle  turbi- 
nated bones.      It  receives  the  opening  for  the  antrum,  frontal  sinus,  and  anterior 
ethmoidal  cells.     (Fig.  77.) 

6.  The  superior  meatus  is  located  between  the  middle  and  superior  turbi- 
nated bones,   and   receives  the  openings   for  the  sphenoidal  sinus  and  for  the 
posterior  ethmoidal  cells.     (Fig.  77.) 

The  antrum  of  Highmore  (maxillary  sinus]  (Figs.  68  and  76)  occupies  the 
interior  of  the  body  of  the  superior  maxilla.  Its  medical  and  surgical  importance 
entitle  it  to  the  following  analytical  consideration  : 

1.  It  has  a  roof,  a  thin  plate  of  bone  that  forms  the  floor  of  the  orbit.      In 
this  roof  is  the  infraorbital  nerve  and  vessels.     (Fig.  51.) 

2.  A  floor  formed  by  the  alveolar  process  of  the  upper  jaw.     The  fangs  of 
the  teeth  may  produce  irregularities  of  this  floor.     (Fig.  76.)     The  surgeon  may 
gain  access  to  the  cavity  by  extracting  a  first  or  second  molar  tooth. 

3.  Inner  ivall. — The  importance  of  this  wall  is  the  presence  of  the  normal 
opening,  by  which   the  antrum    communicates  with  the  nasal  fossae.      (Fig.  77.) 
The  surgeon  may  gain  access  to  the  antrum  for  drainage  by  this  wall. 

4.  Anterior  wall. — On  the  inner  surface  of  this  wall  are  the  anterior  superior 


THE   HEAD   AND   NECK.  117 

dental  canals,  containing  vessels  and  nerves  for  the  teeth.  (Fig.  51.)  On  the 
outer  surface  of  this  wall  is  the  infraorbital  plexus  of  nerves,  formed  by  the 
infraorbital  branches  of  the  fifth  and  seventh  nerves.  Entrance  to  the  antrum  for 
purpose  of  drainage  is  gained  by  going  through  this  wall  too. 

5.  Posterior  ivall. — On  this  you  will  find  the  posterior  dental  canals  for 
nerves  and  vessels  to  the  posterior  teeth  of  the  superior  maxilla.  (Fig.  5  I.)  The 
apex  of  the  antrum  corresponds  to  the  prominence  of  the  cheek. 

W hat  can  you  say  of  the  size  of  the  antrum  of  Highmore,  or  maxillary  sinus  ? 

It  will  contain  about  one  ounce  of  fluid.  It  is  variable  in  size  in  different 
persons.  It  is  longer  in  the  male  than  in  the  female.  A  large  bone  may  have  a 
very  small  antrum,  and  vice  versa. 

IV hat  can  you  say  of  the  floor  of  the  ai/tniui  / 

The  floor  is  the  strongest  wall.  It  is  uneven  on  account  of  the  roots  of  the 
teeth,  the  first  and  second  molars  being  usually  those  producing  the  uneven- 
ness.  These  tooth-roots  may  even  penetrate  the  floor  of  the  antrum,  and  be  the 
exciting  cause  of  disease  of  the  antral  mucous  membrane.  The  antrum  may  be 
divided  into  several  compartments,  or  pockets,  as  they  are  called,  by  bony  par- 
titions of  variable  thickness  and  height,  a  circumstance  which  must  always  enter 


INFRAORBITAL  FORAMEN 

NASAL  NOTCH 

CANINE  FOSSA 

NASAL  SPINE 

INCISIVE  FOSSA 

CANINE  EMINENCE 


BORDER  OF  SPHENO-MAX1LLARY 

FISSURE 
FOR  SPHENOID 

ZYGOMATIC  SURFACE 
MALAR  PROCESS 
POSTERIOR  DENTAL  CANALS 


TUBEROSITY 


FIG.  79. — THE  l.v.vv  MAXILLA.     (Outer  view.) 

as  a  prognostic  factor  in  operations  to  establish  drainage  on  the  antrum.  The 
surgeon  should  ask  himself  after  each  operation,  "  Have  I  drained  the  antrum  or 
only  a  pocket  of  the  antrum  ?  "  A  merchant  had  a  wine-cellar  flooded  with  water. 
He  employed  a  company  to  remove  the  water.  A  hose  was  thrust  through  a 
dark  window  and  the  pump  started.  To  the  dismay  of  the  merchant,  the  experts 
had  thrust  the  hose  into  a  hogshead  of  wine,  and  drained  the  pocket,  instead  of 
the  cellar. 

What  cany 'ou  say  of  the  nerve -supply  of  the  antrum  ? 

The  nerve-supply  of  the  mucous  membrane  of  the  antrum  comes  from  the 
anterior  and  posterior  superior  dental  branches  of  the  fifth  nerve.  You  will 
remember  this  :  The  dental  nerves  supply  the  teeth  ;  the  skin  of  the  lips  and 
cheeks  covering  these  teeth  outside  ;  the  gums  surrounding  these  teeth,  through 
small  branches  called  the  nervuli  gingivales  ;  and,  lastly,  the  mucous  membrane 
of  the  antrum. 

Describe  the  blood-supply  of  the  antrnin  f 

The  internal  maxillary  artery  gives  off  branches  not  only  to  the  teeth  (dental 
branches),  but  also  branches  to  the  gums  (gingival  branches),  and  antral  branches 
to  the  mucous  membrane  of  the  antrum.  These  antral  branches  are  accom- 
panied by  sympathetic  nerves. 


u8 


PRACTICAL  ANATOM\. 


To  what  is  the  nasal  nerve  distributed? 

To  the  septum,  to  the  outer  part  of  the  nose,  and  to  the  two  lower  turbinals. 
This  is  a  sensory  nerve,  a  branch  of  the  ophthalmic  division  of  the  fifth.  It  is 
found  in  the  cranial,  orbital,  and  nasal  cavities.  It  traverses  the  anterior  eth- 
moidal  foramen  and  the  nasal  slit. 

Where  is  the  olfactory  nerve  distributed  ? 

To  the  roof  of  the  fossa ;  to  the  superior  and  middle  turbinals  ;  to  the  upper 
half  of  the  septum  nasi.  (Fig.  75.) 

Where  is  the  spheno-palatine  or  Meckel  's  ganglion  ? 

In  the  spheno-palatine  fossa,  under  the  second  division  of  the  fifth  nerve. 
It  is  the  source  from  which  the  nose  and  mouth  and  palate  derive  their  nerve- 
supply  in  great  part.  (Fig.  75.) 

Tlie  sensory  root  of  Meckel' s  comes  from  the  second  division  of  the  fifth, 
called  the  spheno-palatine  nerves.  (Fig.  53.) 

The  motor  root  comes  from   the   seventh   or  facial  nerve,  through  the  large 


FRONTAL  SINUS 


NASAL  PROCESS  OF  MAXILLA 
LACHRYMAL 

LACHRYMAL  CANAL 

ORIFICE  OF  ANTRUM 

INFERIOR  TURBINAL 

PALATE  BONE 

ANTERIOR  NASAL  SPINE 


ANTERIOR  ETHMOID  CANAL 
POSTERIOR  ETHMOID  CANAL 
OPTIC  FORAMEN 


OS  PLANUM  OF  ETHMOID 


SPHENO-PALATINE  FORAMEN 
VIDIAN  CANAL,  LEADING  INTO  THE 

SPHENO-MAXILLARY  FOSSA 
SPHENOID 


EXTERNAL  PTERY60ID  PLATE 
PALATE  BONE 


FIG.  80. — A  SECTION  OF  THE  SKULL,  SHOWING  THE  INNER  WALL  OF  THE  ORBIT,  THE  BASE  OF 
THE  ANTRUM,  AND  THE  SPHENO-MAXILLARY  FOSSA. 


superficial  petrosal.  This  you  can  see  in  a  groove  under  the  dura,  on  the 
anterior  surface  of  the  petrous  portion  of  the  temporal  bone.  The  nerve  passes 
behind  the  Gasserian  ganglion,  down  through  the  sphenotic  foramen.  It  joins 
here,  at  the  base  of  the  skull,  the  large,  deep  petrosal  branch  of  the  carotid 
plexus.  The  two  now  pass  through  the  Vidian  canal.  The  result  of  the  union 
of  the  large  superficial  petrosal  of  the  seventh  nerve  and  the  large,  deep  petrosal 
of  the  carotid  plexus  is  the  Vidian  nerve.  (Fig.  53.)  The  last  is  the  sympathetic 
root. 

Name  the  brandies  given  off  by  Meckel' s  ganglion.      (Fig.  53.) 
(i)  Branches  to  the  orbital  periosteum;  (2)  branches  to  the  mucous  mem- 
brane of  the  nose;  (3)  anterior  palatine — to  the  roof  of  the  mouth  (Fig.  55)  ; 
(4)  naso-palatine  in  groove  on  nasal  septum  ;  (5)  branches  to  the  upper  pharynx 
behind  luistachian  tube. 

I  introduce  here,  by  consent  of  the  author,  some  conclusions  on  the  opening 
of  the  infundibulum  in  relation  to  the  opening  for  the  antrum  of  Highmore.  I 
have  given  no  special  attention  to  the  subject  in  the  dissecting-room  ;  still,  inci- 


THE   HEAD   AND  NECK.  119 

dentally,  I  have  verified  in  seven   cases  the  views  of  the  author  of  the  follow- 
ing : 


CONTINUED  STUDY  OF  THE  RELATIONS  OF  THE  FRONTAL  SINUS  TO  THE  ANTRUM. 

BY  THOMAS  FILLEBROWN,  M.D.,  D.D.S.,  BOSTON,  MASS. 
PROFESSOR  OF  OPERATIVE  DENTISTRY  AND  ORAL  SURGERY,  DENTAL  SCHOOL  OF  HARVARD  UNIVERSITY. 

(Read  before  the  American  Dental  Association,  August  j,  1897,  and  reprinted  from  the  '''Dental  Cosmos"  for 

December,  1897.) 

"  Last  year  I  made  a  report  of  some  observations  I  had  made  on  the  formation 
of  the  infundibulum,  showing  that  in  many  cases  it  continued  directly  to,  and 
terminated  in  the  foramen  of,  the  antrum,  and  that  a  fold  of  mucous  membrane 
mentioned  by  Merke,  in  1834,  extended  above  the  foramen,  forming  a  pocket, 
from  the  bottom  of  which  the  opening  into  the  antrum  is  situated,  thus  directing 
any  discharge  coming  down  the  infundibulum  into  the  antrum,  so  that,  under  ordi- 
nary circumstances,  no  abnormal  discharge  from  the  frontal  sinus  would  escape 
into  the  nasal  passage  until  the  antrum  was  filled  so  as  to  cause  a  backward 
overflow. 

"  I  mentioned  the  fact  that  Tilleaux,  about  1840,  noticed  that  of  fluid  injected 
into  the  frontal  sinus,  a  great  part  flowed  into  the  antrum,  and  that  Dr.  Cryer,  in 
the  same  year,  mentioned  the  same  circumstance.  He  also  showed  that  a  probe 
could  be  passed  from  the  antrum  into  the  frontal  sinus.  I  also  noticed  that 
Byran  had  mentioned  the  fact  of  occasional  communications  between  the  cavities, 
but  considered  them  anomalies,  and  that  Professor  Harrison  Allen  had  discussed 
the  proliferation  of  empyema  of  the  frontal  sinus  into  the  antrum.  These  obser- 
vations were  of  isolated  cases,  and  were  not  proved  or  considered  indicative  of 
the  normal  anatomy  of  the  parts. 

"  I  reported  that  the  examination  of  eight  different  subjects  showed  that  the 
infundibulum  continued  as  a  deep  groove,  or  tube,  open  on  one  side  down  to  the 
foramen  of  the  antrum,  and  terminated  in  it,  in  every  one  of  the  eight  cases,  and 
that  the  pocket  described  was  present  in  seven  of  the  eight.  This  seemed  to 
imply  that  the  continuation  of  the  infundibulum  to  the  antral  foramen  and  the 
presence  of  the  pocket  membrane  was  the  normal  formation.  During  the  past 
winter  I  had  opportunity  to  examine  fifteen  heads  in  the  Harvard  dissecting- 
room,  and  found  the  infundibulum  continuing  to  the  foramen  of  the  antrum  in 
every  case.  The  membranous  fold  was  present  in  every  case,  except  on  the  left 
side  of  one  subject.  In  this  case  the  process  was  broad  and  flattened  toward  the 
meatus,  and,  though  the  mucous  fold  was  absent,  the  widened  process  served  the 
same  purpose,  as  it  formed  a  cup-shaped  cavity  quite  as  capacious  as  the  pocket 
on  the  other  side. 

"  In  another  case  the  mucous  fold  was  thickened  and  had  considerable  mus- 
cular tissue  intermingled  in  its  substance. 

"  On  the  right  side  of  this  subject  the  infundibulum  was  very  large,  and  in 
place  of  the  ordinary  foramen  there  were  two  openings,  both  quite  large,  fully 
one-fourth  of  an  inch  in  diameter. 

"  In  another  case  the  pockets  were  large,  irregular  in  form,  and  deep,  the 
mucous  fold  completely  covering  the  infundibulum  from  the  foramen  of  the 
frontal  sinus  to  the  antrum. 

"  In  one  subject  the  mucous  fold  was  considerably  calcified.  This  condition 
had  obtained  to  a  degree  throughout  the  whole  system.  This  subject  was 
advanced  in  years.  This  makes  a  total  of  twenty-three  cases  ;  a  number,  I  think, 
sufficient  to  establish  the  fact  of  the  normality  of  the  anatomy  of  the  parts. 

"  The  very  few  variations  only  prove  the  rule.    I  hoped  to  secure  the  co-opera- 


i2o  rRACTICAL    AX  ATOMY. 

tion  of  others  in  making  further  examinations  during  the  winter,  but  the  reprints 
of  my  paper  were  too  long  delayed,  and  the  dissecting  season  was  passed  before 
I  could  communicate  with  anatomists  and  make  the  necessary  arrangements  and 
have  the  benefit  of  the  results  of  the  examinations  of  other  subjects." 


THE    COVERINGS    OF   THE    BRAIN. 

Those  structures  intervening  between  the  brain  and  the  outside  are  brain  pro- 
tectives,and  may  be  called  coverings.  In  number  they  are  three  ;  in  a  collective 
sense,  outer,  middle,  inner.  The  outer  is  called  the  scalp  ;  the  middle,  the  cal- 
varium  ;  the  inner,  the  meninges.  As  above  intimated,  each  of  these  three  cov- 
erings is  a  collective  noun,  and  must  be  reduced,  analytically,  to  its  simplest 
terms  of  individual  structures. 

The  scalp  consists  of  the  following  layers : 

1.  The  skin,  covered  by  a  thick  growth  of  hair  in  primitive  man. 

2.  The  superficial  fascia,  the  distribution  area  where  you  are  to  find  all  the 
arteries,  veins,  nerves,  and  dermal  muscles  of  the  scalp. 

3.  The  occipito-frontalis  muscle,  consisting  of  an  anterior  and  a  posterior 
belly,  connected  by  a  broad  aponeurosis  that  takes  the  name  of  the  muscle. 

4.  A  subaponeurotic  layer  of  connective  tissue,  which  you  can  account 
for  by  consulting  a  paragraph  in  the  introductory  chapter  on  the  non-apposition 
of  anatomical  structures. 

There  are,  then,  four  layers.  The  scalp  moves  .freely.  The  fibrous  covering 
of  the  bone  is  periosteum,  and  its  subperiosteal  connective  tissue  does  not  differ 
from  like  tissue  found  underlying  periosteum  everywhere.  These  two  structures 
do  not  form  integral  parts  of  the  scalp  because  they  do  not  move. 

Dissection. — Remove  the  skin — having  shaved  the  head — by  making  cross- 
incisions  on  the  mid-top  of  the  head,  thus  +. 

In  the  superficial  fascia  of  the  scalp  you  are  to  find  the  following  structures  : 

1.  The  supraorbital  nerve  and  vessels.     (Figs.  16  and  18.) 

2.  The  temporal  branches  of  the  seventh  nerve.     (Fig.  16.) 

3.  The  auriculo-temporal  branch  of  the  fifth  nerve.     (Fig.  16.) 

4.  The  temporal  arteries — superficial — and  veins.     (Fig.  18.) 

5.  The  great  occipital  nerve — second  cervical,  posterior  division.      (Fig.  22.) 

6.  The  small  occipital  nerve — cervical  plexus.     (Fig.  22.) 

7.  The  great  auricular  nerve — cervical  plexus.     (Fig.  22.) 

8.  The  posterior  auricular  artery — branch  of  the  external  carotid. 

9.  The  posterior  auricular  nerve — branch  of  seventh  cranial.     (Fig.  16.) 
The  above  structures  you  have  already  found  in  your  dissection  of  the  face 

and  neck. 

10.  The  dermal  muscles  are  as  follows  (Fig.  14)  : 

1.  Musculus  attrahens  aurem — draws  the  ear  forward. 

2.  Musculus  attollens  aurem — draws  the  ear  upward. 

3.  Musculus  retrahens  aurem — draws  the  ear  backward. 

They  have  origin  and  insertion  as  indicated  in  the  figure.  They  are  insig- 
nificant, and  can  only  be  demonstrated  in  some  cases.  The  function  of  these 
muscles  is  seen  in  some  of  the  domestic  animals — the  dog,  horse,  and  mule. 

The  occipito-frontalis  (Fig.  14)  has  a  posterior  attachment  to  the  outer  two- 
thirds  of  the  superior  curved  line  of  the  occipital  bone  and  to  the  mastoid  process 
of  the  temporal  bone.  This  muscular  belly  terminates  anteriorly  in  a  broad  epi- 


THE   HEAD   AND   NECK. 


121 


cranial  aponeurosis.  Follow  this  forward  to  the  anterior  belly.  The  anterior 
belly  was  described  with  the  face. 

The  calvarium  (Fig.  8 1 )  or  second  covering  of  the  brain  has  three  layers  called 
tables.  They  are  named  and  distinguished  as  follows  :  (i)  an  outer,  tough  and 
resisting  ;  (2)  a  middle  table  which  is  porous  or  spongy,  called  diploe.  This  is 
very  porous  and  contains  many  diploic  veins  that  bleed  rather  freely  during  trephin- 
ing. The  characteristic  of  this  table  of  some  of  the  bones  of  the  cranium  is  to 
become  absorbed.  The  intramural  sinuses  (see  p.  1 13),  as  the  frontal,  ethmoid, 
sphenoid,  mastoid,  may  be  considered  as  owing  their  formation  to  this  process  of 
absorption.  (3)  The  inner  or  vitreous  table  is  hard  and  brittle.  The  inner  surface 
is  grooved  for  the  accommodation  of  the  meningeal  arteries  (Fig.  81),  the  nutrient 
arteries  to  the  dura  mater  and  calvarium. 

The  meninges  form  the  third  or  innermost  of  the  three  grand  protectives  of 
the  brain.  This  covering  consists  of  a  dura  mater,  an  arachnoid,  and  a  pia 


GONION 


OB    EXTERNAL 
OCCIPITAL    PRO- 
TUBERANCE 


BASION 


FIG.  81. — THE  SKULL  IN  SAGITTAL  SECTION. 


mater.  The  arrangement  they  bear  to  each  other  makes  two  physiological 
lymph  spaces:  (i)  a  subdural ;  (2)  a  subarachnoid.  These  terms  are  self- 
explanatory,  and  conform  to  the  rule  of  subs  in  the  introduction. 

The  dura  mater  is  adherent  to  the  bony  walls  of  the  calvarium  and  base  of 
the  skull.  Its  attachments  are  firmer  in  those  localities  where  (i)  great  numbers 
of  nerves  are  leaving  ;  (2)  where  there  are  numerous  foramina  ;  (3)  where  there 
are  many  sutures.  The  base  of  the  skull  possesses  these  three  characters,  hence 
here  the  dura  is  most  intimately  adhered. 

The  dura  mater  has  four  double  processes,  called  :  (i)  Falx  cerebri ;  (2)  falx 
cerebelli ;  (3)  tentorium  cerebelli ;  (4)  diaphragma  sellse.  Each  process  possesses 
(i)  a  free  margin;  (2)  an  attached  margin;  (3)  sinuses  for  the  reception  of 
venous  blood  from  the  brain. 

The  diaphragma  sellae  is  an  inconsiderable  dural  process  attached  to  the 
margin  of  the  sella  turcica,  or  pituitary  fossa,  qn  the  superior  surface  of  the  body 
9 


122 


PRACTICAL  ANATOMY. 


of  the  sphenoid  bone.  In  its  attached  margin  is  the  circular  sinus.  Under  this 
process  of  dura  is  the  pituitary  body.  This  body  is  connected  to  the  tuber 
cinerium  on  the  floor  of  the  third  ventricle  of  the  brain  by  the  infundibulum, 
which  latter  passes  through  an  aperture  in  the  diaphragma  sellae. 

The  falx  cerebri  (Fig.  82)  is  between  the  cerebral  hemispheres.  It  is  attached 
in  front  to  the  crista  galli  of  the  ethmoid  bone  ;  behind,  to  the  tcntorhnn  cerebelli  ; 
above,  to  the  inner  surface  of  the  caharium,  in  the  mid-line,  and  extends  from 
the  tentorium  to  the  crista  galli.  It  contains  in  its  attached  margin  the  superior 
longitudinal  sinus;  in  its  free  margin  its  inferior  longitudinal  sinus.  The 
superior  sinus  contains  the  chords  Willisii,  mechanical  devices  for  strengthening 
and  holding  its  walls  together.  Blood  in  this  sinus  flows  from  before  backward  ; 
the  sinus  is  fed  by  veins  which  open  into  it  from  behind  forward. 


FOURTH  NERVE 


Fall  oerebri 


THIRD  NERVE 

SECOND  NER  VE 


Tentorium 
cerebeUi 


Lateral  sinus 


Superior 
petrusal  sinus 

Falx  oerebelli 

SEVENTH  AND 
EIGHTH 
NERVES 

NINTH,  TENTH,  AND 
ELEVENTH  NER  VES 

TWELFTH  NER  VE 

SECOND  CERVICAL  NERVE 

Ligamentum  denticulatum 


FIFTH 
NER  VE 


FIRST 
CERVICAL 

NER  \  'E    Inferior  petrosal  sinus 


FIG.  82. — THE  CRANIUM  OPENED  TO  SHOW  THE  FALX  CEREKRI,  THE  TENTORIUM  CEREBELLI,  AI 
THE  PLACES  WHERE  THE  CRANIAL  NERVES  PIERCE  THE  DURA  MATER.     (Sappey.) 

The  falx  cerebelli  is  the  smallest  of  the  three  large  dural  processes  of  th( 
dura.  It  is  between  the  cerebellar  hemispheres.  Its  attached  margin  corresponds 
to  the  internal  occipital  crest  of  the  occipital  bone.  It  contains  the  occipital  sinus. 

The  tentorium  cerebelli  is  midway,  both  in  location  and  size,  between  the 
two  preceding  processes.  It  is  between  the  occipital  lobes  of  the  cerebrum  and 
the  cerebellum.  It  protects  the  latter  from  the  weight  of  the  former.  It  is  attached 
to  the  horizontal  part  of  the  occipital  crucial  ridges  posteriorly  ;  anteriorly  and 
laterally,  to  the  superior  border  of  the  petrous  portion  of  the  temporal  bone  and 
to  the  clinoid  processes  of  the  sphenoid  bone.  In  the  occipital  attachment  are 
found  the  lateral  sinuses  ;  in  the  temporal,  the  superior  petrosal  sinuses, 

The  dura  mater  has  sinuses  located  as  follows  (Figs.  82  and  83)  : 

1.  Superior  longitudinal,  in  the  attached  margin  of  the  falx  cerebri. 

2.  Inferior  longitudinal,  in  the  free  margin  of  the  falx  cerebri. 

3.  Lateral,  in  the  occipital  attached  margin  of  the  tentorium  cerebelli. 


THE   HEAD   AND   NECK. 


123 


4.  Superior  petrosal,  in  the  petrosal  margin  of  the  tentorium  cerebelli. 

5.  Inferior  petrosal,  at  the  inner  posterior  border  of  the  petrosa. 

6.  Occipital,  in  the  attached  margin  of  the  falx  cerebelli. 

7.  Cavernous,  external  to  body  of  the  sphenoid  bone. 

8.  Circular,  in  diaphragma  sellae,  around  the  pituitary  body. 

9.  Sigmoid,  on  the  inner  part  of  the  mastoid  process. 

10.  Transverse,  connecting  the  inferior  petrosal ;  also  called  basilar. 

1 1.  Straight,  at  junction  of  falx  cerebri  and  tentorium  cerebelli. 

The  arteries  of  the  dura  mater  are  the  great,  small,  anterior,  and  posterior 
meningeal  ;  the  anterior  and  posterior  ethmoidal ;  and  branches  of  the  occipital 
and  ascending  pharyngeal.  The  nerves  to  the  dura  mater  are  the  sympathetic, 
ophthalmic,  hypoglossal,  the  pathetic,  and  the  Gasserian  ganglion. 

As  you  have  seen  in  your  dissection,  the  dural  sinuses  are  between  the  two 
layers  of  the  dura  mater.  They  are  for  the  reception  and  transmission  of  venous 


Falx  cerebri 


Choroid  plexus 
Veins  of  Galen 


Tentorium 
cerebelli 

Lateral  sinus 

CORPUS 
DENTA  TUM 


CA  UDA  TE 

NUCLEUS 
LATERAL 
VENTRICLE 


Superior  petrosal 

sinus 
MASTOID  ANTRUM 

Lateral  sinus 
MASTOID  PROCESS 


FIG.  83. — CORONAL  SECTION  OF  THE  HEAD  PASSING  THROUGH  THE  MASTOID  PROCESS. 
(From  a  mounted  specimen  in  the  Anatomical  Department  of  Trinity  College,  Dublin.) 


blood  from  the  brain.  The  sinuses  are  lined  by  endothelial  cells,  continuous 
with  the  lining  of  the  veins. 

The  arachnoid  membrane  you  will  know  by  the  glistening  appearance  it 
gives  the  brain.  Externally  it  is  in  relation  with  the  subdural  space  ;  internally 
with  the  subarachnoid  space. 

Where  is  the  subdural  space  located  and  what  does  it  contain  / 

It  is  located  between  the  dura  mater  and  the  arachnoid  membrane,  and  con- 
tains a  small  amount  of  fluid.  Call  this  fluid  subdural. 

The  subaracJmoid  space  is  wJicrc  located  and  contains  what  / 

It  is  located  between  the  arachnoid  membrane  and  the  pia  mater.  It  contains 
the  greater  part  of  the  cerebro-spinal  fluid.  Call  this  fluid  subarachnoid. 

Docs  the  subdural  fluid  communicate  with  the  subarachnoid  fluid  ? 

No  ;  the  two  are  separated  from  each  other  by  the  arachnoid  membrane. 


124 


PR  A  CTICAL    ANA  TOM* . 


h  tlic  pin  j  f  later  a/so  intact,  so  as  not  to  permit  communication  between  the  sub- 
arachnoid  fluid  and  the  ventricular  fluid  in  the  ventricular  cavities  of  the  brain  ? 

No  ;  the  pia  mater  has  many  slits,  by  which  it  permits  the  fluid  in  the  sub- 
arachnoid  space  to  communicate  with  other  lymph  spaces.  The  main  ones  are 
in  the  pia  mater  covering  the  fourth  ventricle.  They  are  three  in  number  :  Key, 
Retzius,  Magendie.  (Fig.  84.) 

The  arachnoid  is  covered  externally  with  endothelial  cells.  It  is  joined  to 
the  pia  by  fibrous  trabeculae,  called  the  subarachnoid  tissue.  At  the  base  of  the 
brain  it  is  separated  from  the  pia  mater  by  the  anterior  and  posterior  subarach- 
noid spaces.  The  anterior  is  between  the  temporo-sphenoidal  lobes  of  the 
cerebrum  and  in  front  of  the  pons  Varolii  ;  the  posterior  subarachnoid  space  is 
between  the  medulla  and  cerebellum.  These  two  spaces  contain  the  greater 


HKLU'ATK  aUBARACHNOID    TIVSfK   <'O.\.\Kt"ri.\<;    THE  Ml\<  IIMill, 
TO    THK   /'/.I    MATKII    OVKH    Til/:'  Cll.\  VKXl  TY  OP   THK  HKAIX 


BRAIN 


POSTER  f  (tit   SI' HA  KM' II- 
HO  ID   SPACE 
/•'O/M.I/A'.V   III-'  KKY  IX   THK  /'/.I   .VATKIt 

n>K.\MK\  01-'  MM1KMHK  f\  THK 
I>IA    MATKK 


/••'ill. I.I/A'.V   <>r  KKT/.irs   !\    THK 
!•/.(    MATER 


FIG.  84. — SCHEMATIC. 

To  show  the  location  of  the  foramina  of  Key  and  Retzius  in  the  pia  mater,  whereby  the  subarachnoid 
fluid  in  the  subarachnoid  space  communicates  with  the  fluid  in  the  fourth  ventricle. 

part  of  the  subarachnoid  fluid.  The  posterior  space  communicates  with  the 
fourth  ventricle  of  the  brain  through  the  pia  mater  by  the  foramina  of  Key  and 
Retzius.  (Fig.  84.) 

Where  is  the  cerebro-spinal  fluid  found  and  ivliat  are  its  uses  t 

The  subarachnoid  or  cerebro-spinal  fluid  is  found  in  the  subarachnoid  spaces 
of  the  brain  and  cord  and  in  the  ventricular  cavities  of  the  brain.  Its  use  is  to 
mechanically  protect  the  nerve  centres  from  shock,  and  to  fill  up  space,  as  fat 
does  in  some  other  parts  of  the  body.  Its  amount  is  estimated  at  less  than 
two  ounces.  The  cerebro-spinal  fluid  of  the  brain  and  cord  communicate. 

Explain  t/ie  special  features  of  the  subarachnoid  space. 

As  shown  in  figure  84,  the  greater  part  of  the  space  between  the  arachnoid 
membrane  and  the  pia  mater  is  occupied  by  delicate  connective  tissue.  It  is  im- 


THE   HEAD   AND   NECK.  125 

possible  to  separate  the  two  membranes  whenever  this  is  the  case.  At  the  base 
of  the  brain  you  will  see  some  well-defined  spaces  on  removing  the  brain. 

The  Pacchionian  glands  will  be  seen  as  little  stubby  hairs  or  even  delicate 
enlargements  on  the  arachnoid  membrane,  in  the  neighborhood  of  the  superior 
longitudinal  sinus.  They  are  enlarged  villi  of  this  membrane.  They  often  per- 
forate the  dura  mater.  Occasionally  they  will  be  found  to  perforate  the  bones 
of  the  skull.  Their  use  is  not  positively  known  ;  but  they  seem  to  transmit 
subarachnoid  fluid  into  the  superior  longitudinal  sinus. 

Of  ivliat  is  the  pia  mater  composed  ? 

It  is  composed  of  vessels  and  connective  tissue. 

Where  is  the  pia  mater  found  in  practical  dissection  on  the  cadaver  ? 

The  pia  mater  is  found  :  (i)  Covering  the  surface  of  the  brain  ;  (2)  in  the 
interior  of  the  brain,  in  the  third  and  lateral  ventricles,  as  velum  interpositum 
and  choroid  plexus  ;  (3)  forming  the  tela  choroidea  inferior  along  the  roof  of 
the  fourth  ventricle.  This  latter  is  perforated  by  three  foramina,  by  which  fluid 
in  the  ventricles  communicates  with  fluid  in  the  subarachnoid  space.  (Fig.  84.) 

SUBARA CHNOID  SPA CE  Superior  longitudinal  sinus  PA CCHIONTA N  BODY 


CORPUS  CALLOSUM 


FIG.  85. — CORONAL  SECTION  THROUGH  THE  GREAT  LONGITUDINAL  FISSURE,  SHOWING 
THE  MENINGES.     (Key  and  Retzius.) 

Distinguish  between  the  dura  mater  surrounding  the  brain  and  the  dura  sur- 
rounding the  spinal  cord  as  follows  : 

1.  Attachment  to  bone,  firmly  and  laxly — periosteal  function. 

2.  Dural  processes,  for  supportive  purposes. 

3.  Dural  sinuses,  for  venous  blood. 

4.  Pacchionian  bodies  ;   Pacchionian  villi. 

These  four  conditions  are  found  in  the  cranial  dura  mater  ;  the  dura  of  the 
cord  has  neither  attachments,  processes,  sinuses,  nor  Pacchionian  bodies. 

To  remove  a  brain  take  the  following  steps  :  If  the  case  is  a  post-mortem, 
then  it  is  necessary  to  conduct  your  work  so  as  to  leave  the  subject  in  a  present- 
able form.  In  this  case  make  (i)  an  incision  from  ear  to  ear  through  the  scalp, 
turn  the  front  flap  down  over  the  face,  the  back  one  down  onto  the  neck  ;  (2) 
cut  through  the  origin  of  the  temporal  muscle,  along  the  complete  temporal 
ridge.  Turn  this  muscle  and  its  heavy  fascia  down  over  the  zygoma. 

To  Mark  the  Calvarium. — Make  a  line  from  one-half  of  an  inch  above  the 
supraorbital  arch  on  each  side,  around  the  head,  passing  through  the  external 
occipital  protuberance.  Caution  :  Avoid  getting  too  low  in  front,  lest  your  incision 
pass  under  the  roof  of  the  orbit.  If  you  fail  to  bring  your  incision  to  the  level 


126  PRACTICAL   ANATOMY. 

of  the  external  occipital  protuberance  you  will  have  trouble  in  removing  the  cere- 
bellum. 

To  Cut  the  Calvarium. — Saw  in  the  line  as  indicated  in  the  preceding 
paragraph.  Avoid  cutting  too  deeply  in  the  temporal  region.  After  you  have 
completed  the  incision  with  the  saw,  take  a  chisel  and  hammer  and  test  your 
work.  If  any  places  remain  uncut,  you  can  easily  finish  loosening  the  calvarium 
with  the  chisel.  The  calvarium  must  be  made  loose  without  cutting  through  the 
dura  mater.  Grasp  the  cut  edge  of  bone  above  the  orbits,  and,  while  an  assistant 
presses  down  on  the  chin,  pull  the  calvarium  backward  ;  as  it  comes  off  you  will 
hear  a  noise,  produced  by  the  separation  of  the  dura  from  the  bone.  On  a 
previous  page  you  have  learned  that  the  dura  has  attachments  to  the  interior  of 
the  cranium. 

Now  make  the  following  observations  : 

1.  Note  on  the  inner  surface  of  the  calvarium  the  meningeal  grooves  for  the 
meningeal  arteries.    These  arteries  are  between  the  dura  and  bone.    They  furnish 
blood   to  both  dura  and  bone.     They  have  nothing  to  do  with  the  blood-supply 
to  the  brain  proper. 

2.  The  Pacchionian  bodies  and  villi  (Fig.  82)  will  be  seen  on  the  outer  sur- 
face of  the  dura  mater,  in  some  cases  where  they  have  perforated  this  structure. 
They  produce,  by  pressure  atrophy,  the  Pacchionian  depressions  in  the  inner  table 
of  the  calvarium.     They  are  a  villous  product  of  the  arachnoid.     Their  function 
is  not  perfectly  understood.     They  are  found  in  great  abundance  in  the  region 
of  the  superior  longitudinal  sinus,  and  even  in  the  sinus  itself. 

3.  You  will  note  the  great  or  middle  meningeal  artery.     It  consists  of 
several  branches,  which  all  spring  from  one  parent  stem  in  the  middle  fossa  of 
the  skull.      It  lies  in  the  connective  tissue  that  held  the  dura  to  the  bone. 

4.  The  superior  longitudinal  sinus  (Figs.  82  and   83)  lies  in  the  mid-line. 
Cut  this  open  from  end  to  end.     Take  note  of  the  large  amount  of  clotted  blood 
it  contains  in  its  posterior  half.      Make  note  also  of  the  chordae  Willisii  in  the 
bottom  of  the  sinus.      Clear  out  the  clotted  blood,  and  these  cords  of  Willis  will 
come  into  view. 

5.  The  Cerebral  Veins. — Cut  through  the  dura,  with  scissors,  one  inch  ex- 
ternal to  the  sinus  just  opened,  from  before  backward,  parallel  with  the  sinus. 
Next  make  a  lateral  incision  from  the  first  incision  to  the  ear.      Do  this  on  both 
sides.     Turn  the  flaps  outward.     Turn  the.  dura  up  over  the  median  line,  and 
see  the  veins  opening  into  the  sinus  from  behind  forward. 

Origin  of  the  Cerebral  Veins. — These  veins  take  blood  from  the  part  of  the 
brain  supplied  by  the  cortical  system  given  off  from  the  circle  of  Willis.  They 
discharge  the  blood  into  the  several  dural  sinuses. 

6.  The  subdural  space  is  exposed  now.     It  is  between  the  dura  and  arach- 
noid.     It  contains  a  small  amount  of  fluid  for  lubrication — fluid  derived  from  a 
source   explained  in   a  previous   paragraph.     This  space   contains  (i)  the  Pac- 
chionian bodies  ;  (2)  the  veins  to  the  sinuses  ;  (3)  the  cranial  nerves  prior  to  their 
emergence. 

7.  The  falx  cerebri  (Fig.  82)  you  will  see  occupying  the  great  longitudinal 
tissure  between  the  cerebral  hemispheres.     Cut  its  attachment  to  the  crista  galli  in 
front,  and  as  you  pull  it  gently  backward,  cut  the  remaining  veins  opening  into 
the  sinus.      In   the  free  margin  of  the  falx  cerebri    is  the  inferior  longitudinal 
sinus. 

8.  The  arachnoid  membrane  is  the  smooth,  glistening,  transparent  structure 
that  you  now  see  covering  the  brain.     It  is  transparent,  for  you  see  the  vessels 
of  the  pia  mater  through  it.     It  is  smooth  on  its  outer  surface,  for  it  is  lubricated 
by  the  subdural  lymph.      It   is   so  very  delicate  you   would   scarcely  suspect  its 
presence.      Under  it  is  the  subarachnoid  space,  also  containing  fluid. 


THE  HEAD   AND   NECK. 


127 


9.  The  Pia  Mater. — As  you  have  just  observed,  you  can  not  remove  the 
arachnoid  from  the  pia  ;  still,  you  can  see  perfectly  the  vessels  of  the  pia  mater 
through  the  arachnoid.  The  presence  of  the  subarachnoid  tissue  prevents 
separation  of  these  two  structures.  (Fig.  84.)  The  pia  mater  is  composed,  as 
you  can  see  on  your  dissection,  of  (i)  arteries  from  the  circle  of  Willis,  taking 
blood  to  the  brain  ;  (2)  veins  attending  these  arteries,  and  finally  opening  into 
the  dural  sinuses  ;  (3)  connective  tissue  holding  these  arteries  and  veins,  as  the 
warp  of  a  carpet  holds  the  woof. 

Remember,  the  individuality  of  the  pia  mater  depends  not  on  arteries  alone, 
not  on  veins  alone,  not  on  connective  tissue  alone ;  but  on  all  three  woven 
together,  the  connective  tissue  being  the  warp,  the  vessels  the  woof. 


Meningeal  branch,  of 
anterior  ethmoidal  artery 


Jfeningfal  branch  of  pos- 
terior ethmoidal  artery 


Middle  meningeal 

artery 

OPHTHALMIC 

DIVISION  OF 

FIFTH  NERVE 


THIRD  NER  YE 

Cavernous  sinus 
FOl'RTH  NERVE 
AUDITORY  AND 
FACIAL  NERVES 

Superior  petrosal  sinus 
Inferior  petrosal  sin-as 
Petro-sijiiamous  sinus 
SPINAL  ACCES- 
SOR Y  NER  VE 
Sigmoid  portion  of 

lateral  sinus 
Posterior  menimjeal 
bran  ch  of  vertebral 
artery 
Left  marginal  sinus 


Left  lateral  sinus 
Superior  longitudinal  sinus 


Circular  sinus 
Carotid  artery 
SIXTH  NERVE 
Basilar  artery 
Basilar  plexus  of  veins 

Auditory  artery 
Vertebral  artery 
GLOSSO-PHARYNGEAL 

AND  PNEUMOGASTRIO 
Anterior  spinal  artery  [N. 
HYPOGLOSSAL 

NER  VE 
SPIN  A  L  A  CCES- 

SOR  Y  NER  VE 

Right  marginal  sinus 


•cipilal  sinus 
Right  lateral  sinus 


FIG.  86. — THE  VENOUS  SINUSKS. 
(From  a  dissection  by  W.  J.  Walsham  in  St.  Bartholomew's  Hospital  Museum.) 


Structures  You  See  on  the  Base. — Place  the  cadaver  so  the  head  will  hang 
over  the  end  of  the  table.  This  position  will  permit  the  brain  to  gravitate  to  a 
slight  degree  out  of  its  bed.  Gently  shake  the  brain  by  rocking  the  head  from 
side  to  side.  Notice  now  the  following  structures  : 

1.  The  frontal  lobe  of  the  cerebrum  in  the  anterior  fossa. 

2.  The  olfactory  lobe,  on  the  under  surface  of  the  frontal  lobe. 

3.  The  optic  chiasm  and  optic  nerves. 

4.  The  internal  carotid  artery — its  cerebral  stage. 

5.  The  third  cranial  nerve — motor  oculi. 

6.  The  tentorium  cerebelli  attached  to  the  petrosa. 

Hints  on  Dissection  of  the  Foregoing  Structures. — Gently  retract  the 
frontal  lobes  and  you  will  see  the  optic  nerves  covered  by  their  prolongation  of 


128  PRACTICAL   ANATOMY. 

arachnoid.  Remove  this  with  one  braimvard  sweep  of  the  forceps,  and  expose 
the  optic  chiasm.  Behind  this  see  the  infundibulum,  attached  above  to  the  brain 
and  below  to  the  pituitary  body.  See  it  passing  through  a  hole  in  the  dia- 
phragma  sellae. 

The  internal  carotid  artery  will  be  seen  to  the  outer  side  of  the  optic  nerve. 
Do  not  call  this  large  artery  the  ophthalmic.  Cut  the  optics  behind  the  chiasm. 
Cut  the  internal  carotid  artery  close  to  the  anterior  clinoid  process.  You  will 
now  expose  the  third  nerve  by  breaking  the  prolongation  of  arachnoid  about  it. 

The  fourth  cranial  nerve  lies  under  the  free  margin  of  the  tentorium.  You 
will  see  the  tentorium  attached  to  the  superior  border  of  the  petrosa  in  front. 
Cut  along  this  border  on  both  sides.  Now  gently  retract  the  brain.  The  fourth 
nerve  will  pass  to  the  outer  side  of  the  posterior  clinoid  process  and  disappear 
under  the  dura  into  the  cavernous  sinus. 

The  fifth  nerve  will  now  be  seen  crossing  the  superior  border  of  the  petrosa, 
near  the  apex.  It  also  disappears  under  the  dura  through  the  trigeminal 
notch. 

The  sixth  nerve  will  be  seen  going  through  the  dura  one  inch  below  the 
dorsum  sellae.  It  passes  beneath  the  dura  to  gain  the  cavernous  sinus  with  the 
third  and  fourth  nerves,  and  the  ophthalmic  branch  of  the  fifth  nerve. 

Find  now  the  seventh  or  facial  nerve,  the  eighth  or  auditory  nerve, 
and  the  auditory  artery  passing  through  the  internal  auditory  meatus  on  the 
posterior  surface  of  the  petrosa.  Note  the  funnel  of  arachnoid  that  accompanies 
these  structures  to  the  foramen.  The  ninth,  tenth,  and  eleventh  nerves  will 
now  be  seen  leaving  the  cranial  cavity  through  the  jugular  foramen.  The 
twelfth  nerve  leaves  as  two  twigs  :  after  passing  through  the  dura  they  unite 
as  one  nerve,  and  leave  the  skull  by  the  anterior  condyloid  foramen. 

FORAMINA  AT  THE  BASE  OF  THE  SKULL  AND  THE  STRUCTURES  THEY  TRANSMIT. 

Foramen  Caecum Transmits  an  emissary  vein. 

Nasal  Slit Transmits  the  nasal  branch  of  the  ophthalmic 

nerve. 

Olfactory  Foramina Twenty  in  number,  transmit  the  olfactory  nerves. 

Optic  Foramina,     ......  Transmit  the   optic   nerves  and  the   ophthalmic 

artery. 

Sphenoidal  Fissure Transmits  third,  fourth,  sixth,  and  first  divisions  of 

the  fifth  nerve,  the  ophthalmic  vein,  and  sym- 
pathetic nerves. 

Foramen  Rotundum,  ....  Transmits  the  second  or  superior  maxillary  divi- 
sion of  the  fifth  nerve. 

Foramen  Ovale,     ......  Transmits  the  third  division  of  fifth   nerve   and 

small  meningeal  artery. 

Foramen  Spinosum, Transmits  the  great  or  middle  meningeal  artery. 

Foramen,  Sphenotic Transmits  internal  carotid  and  the  facial  and 

carotid  petrosals  for  Vidian  nerve. 

Hiatus  Fallopii Transmits  petrosal  branch  of  the  Vidian  nerve. 

Petrosal  Foramen Transmits  the  smaller  petrosal  nerve. 

Carotid  Canal Transmits  internal  carotid  artery  and  sympathetic 

nerves. 

Internal  Auditory  Meatus,  .  .  Transmits  seventh  and  eighth  nerves  and  auditory 

artery. 

Jugular  Foramen Transmits  jugular  vein,  ninth,  tenth,  and  eleventh 

nerves. 

Anterior  Condyloid  Foramen,  Transmits  the  hypo-glossal  nerve — the  twelfth 

nerve. 

Foramen  Magnum, Transmits  (i)  spinal  cord  and  its  meninges;  (2) 

the  vertebral  arteries  and  their  sympathetic 
nerves ;  (3)  the  spinal  accessory  nerve — the 
eleventh  nerve.  Note  the  eleventh  nerve 
coming  up  through  the  foramen,  passing  for- 
ward, and  leaving  the  cranium  with  the  ninth 
and  tenth  nerves  by  the  jugular  foramen. 


THE  HEAD  AND  NECK. 


129 


The  Cavernous  Sinus. — The  sinus  is  located  between  the  apex  of  the 
petrous  portion  of  the  temporal  bone  and  the  sphenoidal  fissure.  Note  that  all 
the  nerves  you  have  just  seen  in  the  table  passing  through  the  sphenoidal 
fissure  also  pass  through  the  cavernous  sinus. 

The  sinus  contains  the  following  structures  : 

1.  The  venous  blood  common  to  dural  sinuses. 

2.  The  cavernous  stage  of  the  internal  carotid  artery. 


KACH   C/M.V/.IA 
XEIi  VE  Off  ITU 
KXI'AI'R  RE- 
I'EIVEX  A  PSU- 
TEVTIOS  III-' 
MATEH 


FIG.  87. — SCHEMATIC. 
To  show  the  dura  mater  forming  sheaths  for  the  nerves  as  they  leave  the  cranium. 

3.  The  sympathetic  plexus  of  nerves  on  the  common  carotid  artery. 

4.  The  ophthalmic  division  of  the  fifth  cranial  nerve. 

5.  The  motor  oculi,  the  third  cranial,  nerve. 

6.  The  patheticus,  the  fourth  cranial,  nerve. 

7.  The  abducens,  the  sixth  cranial,  nerve. 

Dissection. — Remove  the  dura  mater.     Take  hold  of  it  in  the  region  of  the 
frontal    bone,  and    pull  it  back.      It   will  come  off  quite    readily.      Locate    the 


CAVERNOUS    SINUS 
INT.CAROTIO    ARTERY  - 


Fir,.  88. — RELATION  OF  THE  VARIOUS  STRUCTURES  PASSING  THROUGH  THE  CAVERNOUS  SINUS. 


internal  carotid  artery  next  to  the  sphenoid  wall  of  the  sinus.  The  small  nerve 
on  the  artery  is  the  sixth  cranial.  You  will  find  the  others  on  the  outer  wall, 
from  above  downward  :  third,  fourth,  and  fifth. 

The  Gasserian  Ganglion. — Remove  in  the  same  way  the  dura  mater  from 
the  middle  fossa  as  you  did  from  the  anterior,  and  you  will  expose  the  Gasserian 
ganglion  in  a  depression  on  the  anterior  surface  of  the  petrous  portion  of  the 
temporal  bone  near  the  apex.  The  ganglion  lies  between  two  layers  of  subdural 


1 3o  PRACTICAL  ANATOMY. 

connective  tissue,  called  Meckel's  fascia.  The  relation  of  the  ganglion  to  the 
internal  carotid  is  of  great  importance  in  surgical  operations  on  the  ganglion. 

In  figure  86  the  artery  will  be  seen  behind  the  Gasserian  ganglion,  the  third, 
fourth,  sixth,  and  ophthalmic  division  of  the  fifth  nerve,  and  Meckel's  fascia.  In 
other  words,  turn  all  these  nerves  aside  and  you  will  see  the  Gasserian  ganglion 
between  two  layers  of  subdural  connective  tissue  called  Meckel's  fascia.  The  space 
between  these  two  layers  of  fascia  is  called  Meckel's  space.  The  space  through 
which  the  fifth  nerve  passes,  between  the  tentorium  and  the  superior  border  of 
the  petrosa,  near  the  apex  of  the  bone,  is  called  the  trigeminal  notch.  Turn  the 
Gasserian  ganglion  out  of  its  bed  and  cut  through  the  lower  layer  of  Meckel's 
fascia,  and  you  will  find  the  internal  carotid.  In  operations  for  removal  of  the 
Gasserian  ganglion,  this  relation  of  the  ganglion  to  the  artery  must  be  borne  in 
mind,  since  the  only  protection  to  the  artery  is  a  thin  layer  of  Meckel's  fascia. 

Find  the  superior  maxillary  division  of  the  fifth  nerve  leaving  by  the  foramen 
rotundum  in  the  greater  iving  of  the  sphenoid. 

The  inferior  maxillary  division  you  will  find  leaving  by  the  foramen  ovale  in 
the  greater  wing  of  the  sphenoid. 

Dissection  and  study  of — 

1.  The  Gasserian  ganglion,  its  branches  and  relations. 

2.  Meckel's  fascia,  anterior  and  posterior  layers. 

3.  The  middle,  or  great,  and  the  other  meningeal  arteries. 

4.  The  facial  nerve,  the  seventh  cranial  in  the  petrosa. 

5.  The  tympanic  cavity,  the  tympanum  or  middle  ear. 

6.  The  petrosal  stage  of  the  internal  carotid  artery. 

7.  The  cavernous  stage  of  the  internal  carotid  artery. 
Locate  ike  following  anatomical  structures : 

1.  The  middle  meningeal  groove  and  its  artery. 

2.  The  superior  border  of  the  petrosa. 

3.  The  inferior  border  of  the  petrosa. 

4.  The  posterior  surface  of  the  petrosa. 

5.  The  anterior  surface  of  the  petrosa. 

6.  The  internal  auditory  meatus  with  the  seventh  and  eighth  nerves. 

7.  The  hiatus  Fallopii  and  great  petrosal  nerve. 

8.  The  tegmen  tympani  or  roof  of  the  tympanum. 

9.  The  foramen  lacerum  medium.     Sphenotic  fissure. 

10.  The  foramen  spinosum  in  the  alar  spine  of  sphenoid  bone. 

1 1.  The  sphenoidal  fissure  in  the  sphenoid  bone. 

12.  The  foramen  ovale  for  third  division  of  the  fifth  nerve. 

13.  The  foramen  rotundum  for  the  second  division  of  the  fifth  nerve. 

14.  The  anterior,  middle,  and  posterior  clinoid  processes. 
Describe  the  middle  meningeal  artery. 

It  is  a  branch  of  the  first  stage  of  the  internal  maxillary  artery.  External  to 
the  cranium  it  lies  behind  the  internal  pterygoid  muscle.  It  passes  between  the 
two  roots  of  origin  of  the  auriculo-temporal  nerve.  It  enters  the  cranium  by  the 
foramen  spinosum,  in  the  great  wing  of  the  sphenoid  bone,  and  ramifies  between 
the  dura  mater  and  the  bone,  both  of  which  it  supplies  with  blood.  Its  two 
accompanying  veins  are  tributary  to  the  internal  maxillary  vein.  The  middle 
meningeal  artery  divides  in  anterior  and  posterior  branches  which  supply  the 
greater  part  of  the  bones  of  the  cranium.  (Fig.  81.) 

This  vessel  gives  off  the  following  minor  branches  : 

1 .  Small  branches  to  the  Gasserian  ganglion  and  its  adjacent  dura  mater. 

2.  A  branch  through  the  hiatus  Fallopii  to  the  seventh  nerve  and  tympanum. 

3.  Temporal  branches  perforating  the  bone  to  the  temporal  fossa. 

4.  Orbital  branches  passing  through  the  sphenoid  fissure  to  the  orbit. 


THE  HEAD  AND  NECK.  131 

From  what  other  sources  does  tJie  dura  receive  its  blood-supply  ? 

The  anterior  meningeal  arteries  are  in  the  anterior  fossa  of  the  skull.  They 
are  derived  from  the  ethmoidal  branches  of  the  ophthalmic  artery,  and  from  the 
cavernous  stage  of  the  internal  carotid.  The  small  meningeal  is  a  branch  of  the 
first  stage  of  the  internal  maxillary.  It  enters  the  cranium  by  the  foramen  ovale 
with  the  third  division  of  the  fifth  nerve.  The  posterior  meningeal  arteries 
come  from  the  vertebral,  occipital,  and  ascending  pharyngeal. 

Describe  the  cavernous  stage  of  the  internal  carotid  artery. 

It  is  in  the  cavernous  sinus,  but  covered  by  the  endothelial  lining  of  the  sinus. 
(Fig.  86.)  From  the  inner  end  of  its  petrosal  stage  the  artery  ascends  to  the  pos- 
terior clinoid  process  ;  it  then  lies  by  the  side  of  the  body  of  the  sphenoid,  and 
then  gently  curves  upward  between  the  middle  and  anterior  clinoid  processes,  and, 
lastly,  curves  backward  and  perforates  the  roof  of  the  sinus.  (Fig.  86.)  On  the 
outer  side  of  the  artery  is  the  sixth  nerve.  It  is  surrounded  by  sympathetic 
nerves. 

In  this  stage  the  vessel  gives  off  the  following  branches  : 

1.  Branches  to  the  walls  of  the  cavernous  sinus. 

2.  Branches  to  the  Gasserian  ganglion. 

3.  Anterior  meningeal  branches  to  the  dura. 

4.  Branches  to  the  pituitary  body  in  the  sella  turcica. 
Describe  the  petrosal  stage  of  the  internal  carotid  artery. 

It  has  in  this  stage  two  parts  :  An  ascending  part,  in  front  of  the  tympanum 
and  internal  ear  ;  a  horizontal  part,  which  you  will  see  on  turning  the  Gasserian 
ganglion  backward.  On  the  artery  you  will  see  numerous  sympathetic  nerves, — 
the  carotid  sympathetic  plexus, — which  are  ascending  branches  of  the  superior 
cervical  ganglion.  The  carotid,  Vidian,  and  tympanic  are  its  branches. 

WJiat  are  Mcckel' s  fascia,  Meckel 's  space,  Meeker s  cave,  and  the  trigcminal 
notc/i  in  the  literature  of  the  trigeminal  nerve  ? 

Meckel's  fascia  is  the  subdural  connective  tissue  on  and  under  the  Gasserian 
ganglion.  Meckel's  space  is  between  the  two  layers  of  dura,  external  to  the 
cavernous  sinus.  Meckel's  cave  is  a  depression  on  the  anterior  surface  of  the 
petrosa  for  the  Gasserian  ganglion.  The  trigeminal  notch  is  an  osteological  term  ; 
it  is  a  depression  in  the  upper  border  of  the  petrosa,  near  the  apex,  in  which  the 
fifth  nerve  rests  before  expansion  into  the  Gasserian  ganglion.  This  notch  is 
converted  into  the  trigeminal  foramen  by  the  tentorium  cerebelli. 

Describe  the  Gasserian  ganglion. 

This  ganglion  lies  in  Meckel's  cave,  on  the  anterior  surface  of  the  petrosa. 
It  is  simply  an  enlargement  on  the  anterior  or  sensory  root,  as  it  is  called,  of  the 
fifth  cranial  nerve.  Its  posterior  relations  are  the  foramen  lacerum  medium, 
the  great  petrosal  nerve,  and  the  horizontal  part  of  the  petrosal  portion  of  the 
internal  carotid  artery.  Anterior  to  it  is  the  dura  mater.  The  ganglion  gives 
off  or  receives  the  following  branches  : 

1 .  Filaments  from  the  carotid  plexus  of  the  sympathetic. 

2.  Nerves  to  the  dura  of  the  middle  fossa  and  tentorium. 

3.  The  ophthalmic  nerve  to  the  orbit  and  nose. 

4.  The  superior  maxillary  nerve  to  the  upper  jaw. 

5.  The  inferior  maxillary  nerve  to  the  mandibular  region. 

Wliat  is  the  function  of  the  ganglion  and  the  branches  given  off  therefrom  / 
It  confers  the  quality  of  common  sensation  on  all  parts  to  which  it  is  dis- 
tributed. Behind  the  ganglion  lies  a  nerve  that  supplies  the  muscles  of  mastica- 
tion. This  is  the  so-called  motor  root  of  the  fifth  nerve.  This  nerve  has  nothing 
to  do  with  the  ganglion.  It  leaves  the  base  of  the  skull  through  the  foramen 
ovale  with  the  inferior  maxillary  sensory  part  of  the  ganglion.  (Fig.  53.) 

The   tympanum  or  middle  ear  may  be  very  satisfactorily  dissected  by  the 


132  PRACTICAL   ANATOMY. 

student.  Its  small  size  is  no  argument  against  careful  study  of  its  medical  and 
surgical  importance,  its  contents,  and  its  relations,  since  it  is  of  easy  access  for 
dissection,  and  resolvable  into  the  form  of  a  geometrical  cube  for  purposes  of 
aiding  the  memory  and  facilitating  a  comprehension  of  the  relative  position  of 
those  anatomical  structures  that  make  the  middle  ear  of  such  great  importance. 
The  student  should  not  undertake  a  dissection  of  this  part  until  he  has  a  clear- 
cut  idea  of  the  position,  relation,  and  importance  of  each  wall  of  the  cube.  If 
he  begins  his  dissection  knowing  that  the  drum  of  the  ear  forms  the  outer  wall 
of  the  tympanum  proper,  that  the  Eustachian  tube  and  mastoid  antrum  commu- 
nicate with  the  tympanum  by  the  anterior  and  posterior  walls  respectively,  then 
he  will  surely  find  these  structures  and  think  of  them  in  relation  to  the  walls  of 
a  cube.  To  say  nothing  of  the  part  played  by  the  tympanum  in  hearing,  this 
region  is  of  interest  and  importance  for  the  following  reasons  : 

1.  The  temporo-sphenoidal  lobe  of  the  brain  lies  on  its  roof. 

2.  The  floor  of  the  tympanum  lies  on  the  jugular  fossa. 

3.  The  drum  of  the  ear  and  chorda  tympani  are  on  the  external  wall. 

4.  The  mastoid  antrum  and  cells  are  behind  it. 

5.  The  internal  carotid  artery  is  in  front  of  it. 

6.  The  facial  nerve  skirts  two  sides  of  it. 

7.  The  internal  ear  is  in  close  relation  with  it. 

8.  The  drum  of  the  ear  may  become  ruptured. 

9.  The  interossicular  joints  may  become  ankylosed. 
10.   Pus  may  form  in  the  tympanum. 

Size  and  Subdivisions  of  the  Tympanum. — The  tympanum  is  about  one-half 
of  an  inch  in  height  and  one-sixth  of  an  inch  in  width.  It  is  prolonged  forward 
as  the  Eustachian  tube  and  backward  as  the  mastoid  antrum,  so  its  length  is 
difficult  to  determine  :  for  practical  purposes  one-half  of  an  inch  is  near  enough. 
The  subdivisions  are  the  attic  and  tympanic  cavity  proper.  The  latter  is  quite 
narrow,  and  has  the  membrani  tympani  or  drum  as  its  outer  wall  ;  the  former  is 
broader,  contains  most  of  the  bones  of  hearing,  and  has  a  part  of  the  temporal 
bone  as  its  outer  wall.  Remember,  the  tympanum  is  not  horizontal,  but  its 
anterior  end  slopes  downward,  forward,  and  inward  to  the  Eustachian  tube  ;  its 
posterior  end  slopes  upward,  backward,  and  outward  to  the  mastoid  antrum. 

Study  of  the  tympanum  in  which  this  cavity  is  compared  to  a  box.    (Fig.  91.) 

1.  The  roof  of  the  tympanum  is  a  thin  plate  of  bone,  the  tegmen  tympani, 
separating  the  tympanum  from  the  middle  fossa  at  the  base  of  the  skull.      It  is 
perforated  by  foramina  that  transmit  the  petrosal  branches  of  the  seventh  nerve. 

2.  The  floor  separates  the  tympanum  from  the  jugular  fossa,  in  which  fossa 
are  the  internal  jugular  vein,  and  the  ninth,  tenth,  and  eleventh  cranial  nerves. 
In  this  floor  is  an  aperture,  through  which  Jacobson's  nerve,  the  tympanic  branch 
of  the  glosso-pharyngeal,  passes  to  form  the  tympanic  plexus. 

3.  The  outer  wall  of  the  tympanum  is  formed  by  the  drum  below  and  the 
squamosa  above,  these  two  structures  corresponding  to  the  tympanum  proper, 
and  the  attic  respectively.    This  outer  wall  is  pierced  by  the  following  openings  : 
(i)  The  ifcr  clionlie posterius,  by  which  the  chorda  tympani  nerve,  a  branch  of  the 
seventh    cranial   nerve,  enters  the   tympanum  ;  (2)    the   iter  chordtc  aiiterins,  by 
which    the   chorda    tympani   leaves   the    tympanum  ;    (3)   the    (i/aseriau  Jissitre, 
through  which  pass  the  tympatiic  branch  of  the  internal   maxillary  artery,  the 
processus  gracilis  of  the  malleus,  and  the  laxator  tympani  muscle. 

4.  The  inner  isall,   you  will    remember,  is   called   the   fourth    surface  of  the 
'petrosa,  in    Morris'  analysis  of  this  part  of  the  temporal  bone.      This  inner  wall 

contains:  (i)  A  ridge  of  bone  covering  the  seventh  nerve  in  its  passage 
through  the  tympanum,  as  heretofore  explained  ;  (2)  the  fenestra  ovalis,  leading 
into  the  vestibule,  and  to  which  is  attached  the  base  of  the  stapes,  through 


THE   HEAD   AND   NECK.  133 

the  medium  of  a  periosteal  membrane  ;  (3)  the  promontory,  formed  by  a  turn 
of  the  cochlea,  and  covered  by  the  tympanic  plexus  ;  the  promontory  is  below 
and  in  front  of  the  fenestra  ovalis  ;  (4)  the  fenestra  rotunda,  covered  by  the 
membrana  secundaria,  and  communicating  with  the  scala  tympani  of  the 
cochlea  ;  (5)  the  pyramid,  from  whose  summit  emerges  the  tendon  of  the  sta- 
pedius.  A  special  branch  of  the  seventh  nerve  pierces  the  pyramid  for  the 
supply  of  the  stapedius  muscle. 

5.  The  posterior  ivall  commu\\\ca.tQS  with  the  mastoid  antrum.    As  indicated  in 
a  previous  paragraph,  the  mastoid  antrum  is  the  backward  continuation  of  the 
upper  part  of  the  tympanic  cavity,  which  is  called  the  attic. 

6.  The  anterior  wall  of  the  tympanum  presents  but  one  thing  for  examination — 
the  canalis  musculo-tubarius.      This  canal  is  divided  into  an  upper  and  a  lower 
compartment  by  a   horizontal   lamina   of  bone,   called   the  processus  cochleari- 
formis.      The  upper  compartment  lodges  the  tensor  tympani   muscle  ;  the   lower 


FIG.  89. — EAR  AND  TYMPANUM. 

I.  Pinna,  or  auricle.  2.  Concha.  3.  External  auditory  canal.  4.  Membrana  tympani.  5.  Incus. 
6.  Malleus.  7.  Manubrium  mallei.  8.  Tensor  tympani.  9.  Tympanic  cavity.  10.  Eustachian 
tube.  II.  Superior  semicircular  canal.  12.  Posterior  semicircular  canal.  13.  External  semi- 
circular canal.  14.  Cochlea.  15.  Internal  auditory  canal.  16.  Facial  nerve.  17.  Large  petrosal 
nerve.  18.  Vestibular  branch  of  auditory  nerve.  19.  Cochlear  branch. 

is  the  osseous  part  of  the  Eustachian  tube.  These  structures  can  be  readily  seen 
in  dissection.  A  common  broom  straw  or  hairpin  may  be  thrust  through  the 
lower  part  of  the  canalis  musculo-tubarius  as  a  guide. 

Before  you  attempt  to  dissect  the  seventh  nerve  in  its  tortuous  canal  through 
the  petrous  portion  of  the  temporal  bone,  study  well  the  following  branches  this 
nerve  gives  off  between  the  internal  auditory  meatus  and  the  stylo-mastoid  fora- 
men. In  the  auditory  canal  a  short  communicating  branch,  rather  large  and 
fatty,  extends  from  the  seventh  to  the  eighth  nerve.  This  is  called  the  portio 
inter  duram  et  mollem.  The  bony  canal  occupied  by  the  seventh  nerve,  from  the 
time  it  leaves  the  eighth  nerve  until  it  emerges  from  the  stylo-mastoid  foramen,  is 
called  the  aqneductus  Fallopii,  or  the  facial  canal.  In  this  canal  the  following 
branches  are  given  off,  as  you  may  see  by  figure  90. 

I.  From  the  geniculate  ganglion,  the  great  superficial  petrosal  nerve ;  this 
passes  through  the  cartilage  in  the  foramen  lacerum  medium,  and  is  joined  by 


134 


PRACTICAL  ANATOMY. 


some  filaments  from  the  carotid  sympathetic  plexus,  called  the  great  deep  petro- 
sal  nerve.  The  union  of  these  two  makes  a  compound  nerve  called  the  Vidian 
nerve.  This  Vidian,  accompanied  by  vessels  of  like  name,  passes  through  the 
Vidian  canal  and  joins  the  ganglion  of  Meckel,  conferring  on  the  same  motion 
and  sympathetic  qualities.  You  will  recall  the  fact  of  osteology  that  the  Vidian 
canal  is  at  a  junctional  area  formed  by  the  greater  ala  of  the  sphenoid  bone,  its 
lingula  and  pterygoid  process.  Meckel's  ganglion  derives  its  sensory  root  from 
the  spheno-palatine  branches  of  the  superior  maxillary  division  of  the  fifth 
cranial  nerve. 

2.  From  the  geniculate  ganglion,  the  small  superficial  pctrosal  nerve.     This 
nerve  receives  a  communicating  branch  from  the  glosso-pharyngeal  nerve  and 
leaves  the  cranium  by  the  canalis  innominatus  in  the  sphenoid  bone,  between  the 
foramen  ovale  and  foramen  spinosum,  and  joins  the  otic  ganglion  on  the  inner 
surface  of  the  third  division  of  the  fifth  nerve,  near  the  foramen  ovale. 

3.  From  the  geniculate  ganglion,  the  external  pctrosal.     This  nerve  joins  the 


Supraorbifal  5*.* 


,»i»r  V-G: ::--••;  M; 

Q(Uiic Ganij:    ••*' 


FIG.  90. — SCHEME  OF  FACIAL  NERVE  COMMUNICATING  WITH  THE  FIFTH  CRANIAL  NERVE. 

sympathetic  plexus  on  the  great  or  middle  meningeal  artery,  near  the  foramen 
spinosum. 

4.  From  the  nerve-trunk,  below  the  geniculate  ganglion,  the  tympanic  brancli 
to  the  stapedius — the  smallest  muscle  in  the  body.     This  nerve  pierces  the  pyra- 
mid, on  the  inner  surface  of  the  tympanum. 

5.  A  branch  frcm  the  carotid  sympathetic  plexus  joins  the  great  superficial 
pctrosal  just  outside  the  cranium,  to  form  the  Vidian  nerve. 

6.  From  the  main  trunk  of  the  nerve  (8  in  Fig.  90)  a  branch  is  given  oft",  just 
above  the  stylo-mastoid   foramen,  to   communicate  with   the  auricular  branch 
of  the  vagus  nerve. 

7.  From  the  main  nerve-trunk,  just  above  the  stylo-mastoid  foramen,  the  cJwrda 
tympaui  nerve  is  given  off".     This  nerve  passes  upward  through  a  bony  canal,  the 
iter  chordae   posterius,  to  the  tympanum.      It  passes  forward  under  the  mucous 
membrane  of  the  drum  of  the  ear  internal  to  the  manubrium  of  the  malleus.    The 
nerve  leaves  the  tympanum  by  the  iter  chordae  anterius,  or  canal  of  Huguier. 
It  communicates  with  the  otic  ganglion,  passes  internal  to  the  external  pterygoid 


THE   HEAD   AND   NECK.  135 

muscle,  and  joins  the  gustatory  nerve.      It  is  distributed  to  the  submaxillary  and 
sublingual  glands  and  to  the  dorsum  of  the  tongue. 

Dissection  of  the  Seventh  Nerve  in  the  Petrosa  and  of  the  Tympanum. — Locate 

the  following  anatomical  structures  : 

•  « 

1.  The  superior  border  of  the  petrosa. 

2.  Anterior  and  posterior  surfaces  of  the  petrosa. 

3.  The  trigeminal  notch  near  apex  of  petrosa. 

4.  The  cave  of  Meckel  on  anterior  surface  of  petrosa. 

5.  The  horizontal  part  of  the  carotid  canal  and  its  artery. 

6.  The  great  petrosal  nerve  in  the  hiatus  Fallopii. 

7.  The  small  petrosal  nerve  in  its  small  canal. 

8.  The  middle  meningeal  artery  and  foramen  spinosum. 

9.  The  tegmen  tympani  or  tympanic  roof. 

10.  The  internal  auditory  meatus  on  posterior  surface  of  the  petrosa. 

With  a  small  chisel  and  mallet  gently  remove  the  tegmen  in  such  a  manner  as 
not  to  destroy  the  delicate  petrosal  nerves  on  the  anterior  surface  of  the  petrosa, 
and  then  you  can  look  down  into  the  tympanum,  or  middle  ear,  the  roof  now 
having  been  removed  (tegmen).  Now  draw  a  line  from  the  internal  auditory 
meatus  to  where  the  great  petrosal  nerve  is  seen  emerging.  This  line  will  locate 
the  course  of  the  seventh  nerve  in  its  canal  to  the  tympanum.  Now  begin  at  the 
internal  end  of  the  line  just  drawn  and  chip  off  the  bone  until  you  have  completely 
exposed  the  seventh  nerve  to  the  tympanum,  where  you  will  see  the  geniculate 
ganglion  giving  off  petrosal  nerves. 

The  tympanum  may  be  represented  as  a  box  with  an  inner  and  an  outer 
wall,  a  roof  and  a  floor,  an  anterior  and  a  posterior  end.  The  seventh  nerve 
approaches  the  tympanum,  at  a  point  corresponding  to  the  junction  between 
the  roof  and  inner  wall,  near  the  front  end  of  the  box.  The  seventh  nerve 
having  gained  this  point,  now  passes  backward  in  the  angle  between  the  roof 
and  inner  wall  to  the  corner  of  the  box  between  the  inner  wall  and  posterior 
end  of  the  box.  The  nerve  here  makes  a  gentle  turn  and  passes  down  this  cor- 
ner to  the  floor  of  the  box,  and  subsequently  emerges  from  the  base  of  the  skull 
through  the  stylo-mastoid  foramen.  You  may  see  the  geniculate  ganglion  of  the 
nerve  just  where  the  nerve  is  making  the  bend  to  enter  the  tympanum.  Now 
locate  the  nerves  as  described  previously,  and  consult  figure  90. 

BLOOD-SUPPLY  TO  THE  BRAIN. 

Examine  the  base  of  the  brain.  You  notice  very  distinctly  the  arachnoid 
membrane  quite  appreciably  separate  from  the  pia.  In  other  words,  here  you 
see  the  subarachnoid  space.  Now  remove  carefully  the  arachnoid  and  dissect 
the  circle  of  Willis.  You  will  note  the  following  : 

1 .  The  vertebral  arteries  unite  to  form  the  basilar  artery. 

2.  The  basilar  divides  into  the  two  posterior  cerebral  arteries. 

3.  The    internal   carotid  artery    gives    off  three    large    arteries    (Fig.    91)  : 
(i)  The  anterior  cerebral,  in  the  great  longitudinal  fissure  ;  (2)  the  middle  cerebral, 
in  the  fissure  of  Sylvius  on  the  central  lobe  ;  (3)  the  posterior  communicating,  to 
the  posterior  cerebral. 

The  arachnoid  membrane,  it  will  be  observed,  stretches  across  from  frontal 
to  temporo-sphenoidal  lobe,  so  as  almost  to  obscure  the  fissure  of  Sylvius.  Cut 
this  membrane  with  the  scissors,  gently  part  the  lobes,  and  you  will  see  the 
island  of  Reil,  on  which  is  the  middle  cerebral  artery  with  its  vein. 

The  anterior  communicating  artery  is  very  short,  one-eighth  of  an  inch 
being  an  average  length  in  a  number  of  cases.  You  will  find  it  extending  from 
one  anterior  cerebral  artery  to  the  other. 


i36 


PR  A  CTICAL    ANA  TO.  M  J . 


The  ganglionic  or  terminal  end  arteries  will  be  seen  in  very  great  numbers 
on  lifting  the  middle,  posterior,  and  anterior  cerebral  arteries.  They  are  very 
minute.  Look  closely,  and  you  will  see  them  passing  through  minute  perfora- 
tions to  the  interior  of  the  brain  through  the  perforated  spaces.  (Fig.  92.) 

The  interpeduncular  space  has  (i)  boundaries;  (2)  contents.  The  con- 
tents form  the  floor  of  the  third  ventricle.  The  boundaries  are  important 
structures  on  the  base  of  the  brain  which  I  wish  you  to  study  carefully. 
(Fig.  92.) 

The  Boundaries  of  the  Interpeduncular  Space. — (i)  Antero-laterally,  optic 
chiasm  and  optic  tracts ;  (2)  postero-laterally ,  pons  Varolii  and  crura  cerebri. 

Contents  of  Interpeduncular  Space. — (i)  The  tuber  cinereum  ;  (2)  infundibulum, 
pituitary  body  ;  (3)  the  corpora  albicantia,  part  of  the  fornix  ;  (4)  posterior 


Anterior  cerebral 
artery 


Middle  cerebral 

artery 
Internal  carotid 

artery 
Poslero-median 

perforating 
Posterior  cerebral 

artery 

Superior  cerebellar 
artery 

Anterior  inferior 
ccrebellar  artery 


Vertebral  artery 


Posterior  inferior 
cerebellar  artery 


A  nterior  com- 
municating 
artery 

Antero-lateral 
perforating 

A  nttrior  clioroid 

Posterior 
communicating 
artery 

Posterior  choroid 

Basilar  artery 
Cfnis  cerebelli,  cut 


Anterior  spinal 
artery 


FIG.  91. — THE  ARTERIES  OF  THE  BRAIN. 
(From  a  preparation  in  the  Museum  of  St.  Bartholomew's  Hospital.) 

perforate   space,  for   terminal   end   arteries ;   (5)  the  third   cranial   nerve,  mot 
oculi  nerve. 

Notice  in  particular  : 

1.  The  optic  tracts  crossing  the  crura  cerebri. 

2.  The  third  nerve,  motor  oculi,  between  the  crura  cerebri. 

3.  The  terminal  end  arteries  from  the  circle  of  Willis.     (Fig.  91.) 

4.  The  basilar  artery  on  the  body  of  the  pons  Varolii.     (Fig.  91.) 

5.  The  fourth  nerve,  coming  out  between  the  pons  and  crus  cerebri. 

6.  The  fifth  nerve,  coming  from  the  side  of  the  pons  Varolii. 

7.  The  sixth  nerve,  coming  through  between  the  pons  and  medulla. 

8.  The  seventh  and  eighth  nerves,  between  the  olivary  and  restiform  bodies. 

9.  The  ninth,  tenth,  and  eleventh  nerves,  between  the  olivary  and  restiform 
bodies. 

10.  The  twelfth  nerve,  between  the  pyramid  and  olive. 


THE  HEAD  AND  NECK. 


'37 


Two  systems  of  circulation  are  given  off  from  the  circle  of  Willis:  (i) 
Tlic  ganglionic ;  (2)  tlie  cortical.  You  have  just  seen  the  ganglionic  or  end 
arteries  entering  the  brain  by  the  perforated  spaces.  The  cortical  arteries  and 
their  veins  form  the  woof  of  the  pia  mater,  the  warp  of  which  is  connective  tissue. 


i .   From  what  source  docs  the  brain  receive  its  blood  ? 
The  brain  is  supplied  with  blood  by  the  circle  of  Willis. 


OPTIC  THALAMUS 


OPTIC  TRACT 
TUBER  CINEREUM 

POSTERIOR  PER- 
FORATED SPACE 

CORPUS  GENICU- 
LA  TUM  EXTKRNUM 

CORPUS  GENICU- 
LA  TUM  INTERNUM 


PYRAMIDAL  BODY 
OLIVARY  BODY 

ARCIFORM  FIBRES 


ISLAND  OF  REIL 
PITUITARY  BODY 


CORPORA 
ALBICANTIA 

CRUS  CEREBRI 


PONS  VAROLII 


GREA  T  HORIZONTA  L 

FISSURE 
FLOCCULUS 

FORAMEN  CAECUM 


SPIN  A  L  A  CCESSOR  Y 
NERVE 


FIRST  CER  VICAL  NER  VE 

ANTERO-LATERAL  GROOVE 

OF  SPINAL  CORD 
ANTERIOR  COLUMN  OF 
SPINAL  CORD 

FIG.  92. — SURFACE  ORIGIN  OF  THE  CRANIAL  NERVES.     (After  Allen  Thomson.— Quain.) 

2.  How  is  this  circle  formed  ? 

It  is  formed  by  an  anastomosis  between  branches  of  the  internal  carotid  and 
vertebral  arteries. 

3 .  How  does  the  internal  carotid  reach  the  brain  ? 

It  comes  through  the  carotid  canal  and  sphenotic  foramen,  and  gives  off:  (i) 
The  anterior  cerebral  ;  (2)  the  middle  cerebral  ;  (3)  the  posterior  communi- 
cating. 

4.  Hoiv  docs  the  vertebral  artery  reach  tJie  brain  ? 

It  passes  through  the  foramina  in  the  transverse  processes  of  the  cervical 
vertebrae  and  the  foramen  magnum.  It  divides  into  the  two  posterior  cerebral 
arteries. 

5 .  How  is  the  blood  returned  from  the  brain  / 

The  blood  from  the  ganglionic   system  is  returned  to  the  straight  sinus  by 


138  PRACTICAL  ANATOMY. 

the  veins  of  Galen.     (Fig.  82.)     The  blood  from  the  cortical  system  is  returned 
by  various  veins  to  the  several  dural  sinuses. 

6.  What  becomes  of  the  blood  in  the  sinuses  / 

The  sinuses  converge  to  form  the  internal  jugular  vein.  This  vein  is  made 
up  at  the  jugular  foramen,  and  leaves  it  in  company  with  the  ninth,  tenth,  and 
eleventh  cranial  nerves. 

7.  Do  the  branches  given  off  from  the  ganglia nic  system  communicate  until  one 
another  or  with  branches  of  the  cortical  system  ? 

No. 

8.  Where  do  the  branches  forming  the  ganglionic  system  take  their  origin,  and 
hoiv  are  they  named? 

They  originate  from  the  circle  of  Willis  and  from  its  primary  branches  for  an 
inch  beyond  the  circle.  They  are  named  : 

Antero-median,  from  the  anterior  communicating  artery. 
Antero-lateral,  from  the  middle  cerebral  artery. 
Postero-median,  from  the  posterior  cerebral  artery. 
Postero-lateral,  from  the  posterior  cerebral  artery. 

9.  What  is  the  most  important  function  of  this  system  of  circulation  / 

To  supply  blood  to  the  basal  ganglia,  the  most  important  part  of  the 
brain. 

10.  Name  the  most  important  branch   of  the  ganglionic  system,  and  give  its 
surgical  importance. 

The  lenticulo-striate  artery.  It  is  the  largest,  and  most  frequently  the  seat 
of  embolism  or  hemorrhage.  It  passes  through  the  internal  capsule. 

1 1 .  Do  all  the  branches  of  the  ganglionic  system  supply  basal  ganglia  / 

No  ;  the  anterior  and  posterior  choroid  branches  supply  the  choroid  plexuses 
of  the  lateral  ventricles  and  some  minor  adjacent  parts. 

1 2.  Has  any  part  of  the  ganglionic  system  anything  to  do  with  the  formation 
of  the  pia  mater  ? 

As  mentioned  in  a  previous  paragraph,  the  anterior  and  posterior  choroid 
arteries  are  branches  of  the  ganglionic  system,  but  they  do  not  supply  basal 
ganglia ;  they  supply  the  choroid  plexuses,  in  the  lateral  ventricles,  and  these 
plexuses,  with  the  velum  interpositum,  are  extensions  from  the  general  pia 
mater  on  the  surface  of  the  brain  to  equally  superficial  parts  of  the  brain, 
apparently,  but  not  really,  on  the  interior  of  the  brain. 

13.  Arc  the  terms  pia  mater  and  cortical  system  of  circulation,  for  practical 
purposes,  synonymous  / 

Yes  ;  the  pia  mater  consists  of  vessels,  arteries  and  veins,  and  connective 
tissue  ;  the  arteries,  for  the  most  part,  originate  beyond  the  confines  of  the  gang- 
lionic system.  The  pia  mater  is  applied  to  every  part  of  the  outer  surface  of  the 
brain  ;  it  reaches  into  the  fissures  and  sulci.  It  forms  the  velum  interpositum 
and  the  choroid  plexuses. 

1 4.  How  are  the  cerebral  veins  classified  / 

They  may  be  grouped  as  ganglionic,  basilar,  and  cortical,  (i)  The  central 
or  ganglionic  veins  come  together  to  form  the  veins  of  Galen,  having  gathered 
in  their  course  the  veins  of  the  choroid  plexuses  and  velum  interpositum. 
The  veins  of  Galen,  from  the  two  hemispheres,  unite  to  form  the  common  vein 
of  Galen,  a  trunk  about  one-half  of  an  inch  in  length  ;  this,  as  seen  previously, 
opens  into  the  straight  sinus.  (2)  The  basilar  veins  collect  the  blood  from  the 
under  surface  of  the  cerebrum,  and  feed  the  petrosal,  cavernous,  and  lateral 
sinuses.  (3)  The  cortical  veins  gather  the  blood  from  the  outer  and  inner 
surfaces  of  the  hemispheres  and  feed  the  superior  and  inferior  longitudinal 
sinuses  in  the  attached  and  free  margins  of  the  falx  cerebri  respectively. 


THE  HEAD  AND  NECK.  139 

Find  the  following  fissures  and  their  contents  : 

1.  Tlie  great  longitudinal  fissure  contains  :     (i)  The   falx   cerebri    with    its 
superior  and  inferior   longitudinal   sinuses  ;  (2)  the  corpus  callosum,   on   which 
you    may    see    the    anastomosis    between   the    anterior    and   posterior   cerebral 
arteries. 

2.  The  great  transverse  fissure,  between  the  occipital  cerebral  lobes  and  the 
cerebellum.      It  contains  the  tentorium  cerebelli. 

3.  The  fissure  of  Sylvius,  bounded  below  by  the  temporo-sphenoidal  lobe; 
above  by  the  frontal  and  parietal  lobes.     It  contains  :   (i)  The  island  of  Reil,  or 
central  lobe  of  the  cerebrum  ;  (2)  the  middle  cerebral  artery  and  vein  and  their 
numerous  branches. 

4.  The  fissure  of  Rolando  is  between  the  ascending  convolutions  of  the  frontal 
and  parietal  lobes.      Its  surgical  importance  is  due  to  the  fact  of  the  location  of 
the  cortical  motor  areas  about  this  fissure. 

5.  The  occipito-parietal  fissure  is  very  imperfect.     As  its  name  implies,  it  is 
between  the  parietal  and  occipital  lobes. 

Dissection  of  the  brain  does  not  belong  to  dissecting-room  anatomy,  hence 
the  reader  is  referred  to  Morris  for  this  very  interesting  and  instructive  part  of 
anatomy. 


THE  ORBIT  AND  ITS  CONTENTS. 

For  dissecting-room  purposes,  the  following  points  seem  of  practical  or 
rather  demonstrable  importance  : 

i.  Geometry  of  the  Orbit. — Roof,  floor,  outer  wall,  inner  wall,  base,  apex, 
angles,  and  cavity. 

The  roofis  of  importance,  since  it  separates  the  cavity  of  the  orbit  from  the 
frontal  lobes  of  the  brain.  A  missile  may  reach  the  brain  in  this  way,  since  this 
roof  is  often  very  thin. 

The  floor  is  of  importance  (i)  because  it  forms  a  partition  between  the  orbit 
and  the  antrum  of  Highmore,  or  maxillary  sinus  ;  (2)  because  it  is  traversed  by 
the  infraorbital  canal,  in  which  are  the  infraorbital  nerve  and  vessels. 

The  inner  wall  is  in  close  relation  with  the  nasal  fossae,  and  the  ethmoid  cells, 
the  os  planum  of  the  ethmoid,  and  the  lachrymal  bones  form  a  large  part  of  the 
partition  between  these  cavities. 

The  outer  wall  is  formed  by  the  orbital  plates  of  the  sphenoid  and  malar 
bones,  but  is  of  no  special  importance. 

The  apex  of  the  orbit  transmits  the  optic  nerve  and  the  ophthalmic  branch 
of  the  internal  carotid  artery.  The  apex  is  occupied  by  the  optic  foramen,  be- 
tween the  two  pedicles  of  the  lesser  ala  of  the  sphenoid  bone. 

The  base  of  the  orbit  is  of  great  importance  on  account  (i)  of  its  architectural 
construction,  combining  beauty,  strength,  and  protection  ;  (2)  of  the  large  num- 
ber of  anatomical  structures  in  this  region. 

Note  about  the  base  of  the  orbit : 

1.  The  laclirymal  gland  (Fig.  104),  under  the  external    angular  process   of 
the  frontal  bone,  in  a  fossa  called  the  lachrymal  fossa.     This  is  called  the  orbital 
part  of  the  gland  or  the  superior  lachrymal   gland  ;  the  part  of  the  gland  that 
protrudes  below  this  is  called  the   palpebral  portion   or  the  inferior  lachrymal 
gland. 

2.  The  S2ipraorbital  foramen  (it  may  be  double)  transmits  the  supraorbital 
nerve  and  vessels.     (Figs.  98,  103.)     The  vessels  are  branches  of  the  ophthalmic. 


140 


PRACTICAL  ANATOMY. 


The  nerve  is  a  branch  of  the  frontal  part  of  the  ophthalmic,  itself  a  branch  of 
the  fifth  cranial  nerve. 

3.  The  trochlea  is  found  on  the  inner  wall,  near  the  base  of  the  orbit. 
Around  this  trochlea  plays  the  tendon  of  the  superior  oblique  muscle  of  the 
eyeball.  (Fig.  100.)  Here,  too,  occurs  the  anastomosis  between  the  supra- 
trochlear  branch  of  the  frontal  and  the  infratrochlear  branch  of  the  nasal  nerve. 

The  nasal  duct  has  its  beginning  in  the  internal  inferior  angle  of  the  orbital 
base.  (Fig.  104.)  By  this  duct  excessive  tears  reach  the  nasal  fossae. 


PALPEBRAL  FISSURE 
INNER  CANTHUS 


OUTER  CANTHUS 


TENDO  OCULI  DELAMINATES  INTO  SUPERIOR  AND 
INFERIOR  PALPEBRAL  RAMI 

Tendo  oouli  or  internal  tarsal 
ligament 


INFERIOR  TARSAL  LIGAMENT 

FIG.  93. — TENDO  OCULI  AND  TARSAL  CARTILAGES. 

The  infraorbital  nerve  (Fig.  51),  emerges  from  the  orbit  by  the  infraorbital 
foramen  just  below  the  base  of  the  orbit.  This  sends  off  anterior  superior 
branches  to  the  teeth  just  prior  to  its  emergence. 

The  tendo  oculi  crosses  the  lachrymal  sac  in  front  (Fig.  94),  giving  off  an 
aponeurosis  to  the  same.  Observe  the  caruncula  lachrymalis  between  the  t\vo 
diverging  rami  of  the  tendo  oculi. 

The  tendo  oculi,  or  internal  tarsal  ligament,  has  its  origin  from  the  nasal 
process  of  the  superior  maxilla.  (Fig.  10.)  The  superior  and  inferior  tarsal 

1 1 15J 


FIG.  94. — RELATIONS  OF  THE  EYE  AND  THE  LACHRYMAL  EXCRETORY  APPARATUS. 
I,   I.    Canalicirii.     2,    2.    Puncta  lachrymalia.     3,  3.    Inner  extremity  of  tarsal   cartilage.     4,    4.   Free 
borders  of  lids.     5.  Lachrymal  sac.     6.  Attachment  to  maxillary  bone  of  superior  tendon.     7.   Bifur- 
cation of  lachrymal  sac.     8,  8.  Two  branches. 


ligaments,  of  periosteal  derivation  (Fig.  21),  are  attached  to  the  margin  of  the 
base  of  the  orbit  both  above  and  below.  The  external  tarsal  ligament  is  not 
divided. 

The  Angles  of  the  Orbit. 

1 .  The  superior  internal.     This  contains  the  anterior  and  posterior  etJnnoidal 
foramina.     The  former  transmits  the  anterior  ethmoidal  artery  and  nasal  nerve  ; 
the  latter,  the  posterior  ethmoidal  artery. 

2.  The  superior  external  angle.      This   contains  in  front  the  lachrymal  fossa 
already  described,  and  posteriorly  the  sphcnoichil  fissure.      This  fissure  transmits 


THE  HEAD  AND  NECK. 


141 


the  third,  fourth,  sixth,  and  the  three  divisions  of  the  ophthalmic  branch  of  the 
fifth  nerve,  the  ophthalmic  vein,  and  some  minor  structures. 

3.  The  inferior  external  angle.      In  this  is  the  spheno-maxillary  fissure.    This 
fissure  transmits  the  superior  maxillary  nerve  and  its  orbital  branches,  the  ascend- 
ing branches  from  Meckel's  ganglion,  the  infraorbital  branch  of  the  internal  max- 
illary artery  and  its  vein. 

4.  The  inferior  internal  angle  contains  the  beginning  of  the  osseous  part  of 
the  lachrymal  apparatus  that  conveys  tears  to  the  nasal  fossae.     This  apparatus 
will  be  considered  under  the  head  of  orbital  contents.      (Fig.  104.) 

The  periosteum  of  the  orbit  (Fig.  95)  lines  the  walls  of  the  cavity, 
delaminates  at  the  orbital  margin  of  the  base,  one  layer  uniting  with  the  peri- 
osteum externally,  the  other  layer  forming  the  tarsal  ligaments  and  tarsal 
cartilages  above  and  below.  The  orbital  fascia  is  to  the  contents  of  the  orbit, 
other  things  equal,  what  the  deep  fascia  of  the  thigh  is  to  the  structures  of  the 
thigh.  Keep  this  in  mind,  for  here,  as  in  the  thigh,  you  will  find  sheaths, 
capsules,  and  septa  derived  from  this  fascia. 

In  your  dissection  you  will  find  the  following  structures — 

1.  The  optic  nerve — the  special  nerve  of  the  sense  of  sight.     (Fig.  100.) 

2.  The  motor  oculi  nerve,  or  third  nerve.      (Fig.  98.) 


OPTIC  FORAMEN 


DELAMINATION  OF  THE  ORBITAL 
PERIOSTEUM 


arsal  ligament 


Tarsal  cartilage 


PALPEBRAL  FISSURE 


ORBITAL  PERIOSTEUM 


OHBITAL  PERIOSTEUM 


FIG.  95. — SCHEMATIC  REPRESENTATION  TO  Snow  RELATION  OF  PERIOSTEUM  TO  TARSAL  CARTI- 
LAGES AND  TARSAL  LIGAMENTS. 


3.  The  patheticus,  or  fourth  nerve.     (Fig.  98.) 

4.  The  abducens,  or  sixth  nerve.     (Fig.  98.) 

5.  Ophthalmic  branch  of  the  fifth  nerve.      (Fig.  98.) 

6.  The  lachrymal  gland  and  its  capsule.      (Fig.  103.) 

7.  The  ophthalmic  artery  and  its  branches.      (Fig.  103.) 

8.  The  ophthalmic  vein  and  its  branches.      (Fig.  103.) 

9.  The  ciliary  ganglion  and  its  branches.     (Fig.  98.) 

10.  The  orbital  connective  tissue  and  fat. 

11.  The  levator  palpebrae  muscle.      (Fig.  100.) 

12.  The  superior  rectus  muscle.      (Fig.  100.) 

13.  The  external  rectus  muscle.      (Fig.  99.) 

14.  The  inferior  rectus  muscle.      (Fig.  99.) 

15.  The  internal  rectus  muscle.      (Fig.  99.) 

1 6.  The  superior  oblique  muscle.     (Fig.  100.) 

17.  The  inferior  oblique  muscle.      (Fig.  100.) 

1 8.  The  capsule  of  Tenon. 

19.  The  eyeball  with  sclerotica  and  iris.     (Fig.  99.) 
Dissection  of  the  Orbital  Contents — Steps  : 

I.    Remove  the  orbital  plate  and  supraorbital  arch  by  cutting  through  the 


142 


PRACTICAL  ANATOMY. 


internal  and  external  angular  processes  of  the  frontal  bone.    (Fig.  96.)    Carefully 
remove  the  bone  without  injuring  the  periosteum  of  the  orbit. 

2.  Cut  through  the  orbital  periosteum  and  find,  immediately  under  the  peri- 
osteum, the  frontal  nerve.  The  frontal  nerve  lies  on  the  levator  palpebrae  with  the 
supraorbital  artery  and  vein.  It  is  a  branch  of  the  ophthalmic  part  of  the  fifth 


Internal  rectus  muscle 


Superior  oblique  muscle 


Trochlea 


Levator  palpebrse  superioris 
muscle,  cut 


External  rectus  muscle 

Inferior  oblique  muscle 
Superior  rectus  muscle 


Levator  palpebrae  superior-is 
muscle,  cut 


FIG.  96. — VIEW  OF  LEFT  ORBIT  FROM  ABOVE,  SHOWING  THE  OCULAR  MUSCLES 
(From  Hirschfeld  and  Leveille. ) 


FIG.  97. — MUSCLES  OF  THE  EYE. 
I.  Tendon  of  Zinn.     2.   External  rectus  divided.     3.  Internal  rectus.     4.  Inferior  rectus.     5-   Superior 
rectus.     6.  Superior  oblique.      7.    Pulley  for  superior  oblique.      8.   Inferior  oblique.      9.   Levator 
palpebne  superioris.      10,  10.    Its  anterior  expansion.      II.  Optic  nerve. 


nerve.  You  will  see  it  divide  into  two  branches:  (i)  the  supratrochlear  and 
(2)  the  supraorbital.  The  supratrochlear  inosculates  with  the  infratrochlear 
branch  of  the  nasal  nerve.  The  supraorbital  comes  through  the  supraorbital 
foramen,  and  is  distributed  to  the  forehead  and  inner  part  of  the  upper  eyelid. 

The  levator  palpebrae  superioris  muscle  (Fig.  97)  lies  under  the  preceding 
frontal  nerve.     It  is  inserted  into  the  tarsal  ligament  of  the  upper  lid.     It  lies  orv 


THE   HEAD   AND   NECK. 


143 


the  superior  rectus  muscle.  Cut  the  muscle  in  the  middle,  turn  the  ends  out  of 
the  way,  and  expose  the  superior  rectus  muscle.  (Fig.  96.) 

The  Superior  Rectus  Muscle  (Fig.  96). — This  muscle  lies  under  the  levator 
palpebrae.  It  is  inserted  into  the  sclerotic  coat  of  the  eyeball.  Cut  it,  and 
turn  the  ends  aside.  You  will  see  under  this  muscle  a  bed  of  fat.  In  the 
centre  of  the  bed  of  fat  and  connective  tissue  is  the  optic  nerve.  (Fig.  103.) 

The  Optic  Nerve. — To  the  outer  side  of  this  nerve  you  will  see  the  external 
rectus  muscle.  Between  the  nerve  and  this  muscle  you  will  see  the  ciliary  ganglion. 

Study  the  ciliary  ganglion  according  to  this  outline  (Fig.  98)  : 

1.  Location  between  the  optic  nerve  and  external  rectus  muscle. 

2.  Size,  about  as  large  as  a  pin's  head,  but  spider-like. 

3.  Roots  :   (i)  A  motor,  from   the  branch  of  the  third  nerve  to  the  inferior 
oblique;    (2)   a  sensory,  from   the   nasal    nerve;   (3)  a    sympathetic,   from    the 
cavernous  plexus. 

4.  Distribution  and  function.      Branches   are   given   off  from   this  ganglion, 
called  the  short  ciliary  nerves.      They  go  with   the  optic  nerve  surrounding  the 

LENTICULAR  GANGLION 
SUPERIOR  DIVISION  OF  THE  THIRD  NERVE 

NASAL  H RANCH  OF  OPHTHALMIC 


SUPRAORKITAL 
NER  VE 


SHORT  CILIARY 
NER VES 


BRANCH  OF  THIRD  TO 
INFER  [OR  OBLIQUE 


LONG  ROOT  OF  LENTICU- 
LAR GANGLION 

4 

OPTIC  NER  VE 


THIRD  NERVE 
SIXTH  NERVE 
GASSERIAN  GANGLION 


OPHTHALMIC  DIVISION 
OF  FIFTH  NERVE 


SHORT  ROOT  OF  SYMPA THETIC  ROOT  OF  LENTICULAR 

LENTICULAR  GANGLION  GANGLION 


FIG.  98. — NERVES  OF  THE  ORBIT,  FROM  THE  OUTER  SIDE. 
(From  Sappey,  after  Hirschfeld  and  Leveille.) 


same.  On  piercing  the  sclerotic  coat  they  are  joined  by  the  long  ciliary 
branches  from  the  nasal  nerve.  (Fig.  98.)  These  branches  are  distributed  to 
the  iris  and  ciliary  muscle. 

From  wliat  source  does  the  ciliary  ganglion  derive  its  sympathetic  influence,  and 
hoi*.'  docs  the  same  enter  the  orbit  ? 

It  derives  it  from  the  superior  cervical  ganglion.  The  ascending  fibres  enter 
the  cranium  on  the  internal  carotid  artery.  Here  some  fibres  accompany  the 
branches  of  this  artery  to  the  brain.  Other  fibres  leave  the  artery  in  its  cavern- 
ous stage,  pass  through  the  sphenoidal  fissure  to  the  orbit,  and  supply  the  ciliary 
or  lenticular  ganglion. 

Give  the  influence  of  paralysis  of  tlie  third  nerve  on  t/ie  iris. 

Since  the  iris  derives  its  motor  influence,  through  the  ciliary  ganglion,  from 
the  third  nerve,  loss  of  power  of  contraction  of  the  pupil  would  follow. 

The  Optic  nerve,  you  will  find,  is  surrounded  by  very  small  nerves  and 
arteries.  (Figs.  98  and  103.)  The  nerves  are:  (i)  Short  ciliary,  from  the 
ciliary  ganglion  ;  (2)  long  ciliary,  from  the  nasal  nerve.  The  arteries  are  ciliary, 
derived  from  the  ophthalmic  or  some  of  its  branches.  The  optic  nerve  derives 
its  sheath  from  the  dura  mater. 


144 


PRACTICAL  ANATOMY. 


The  external  rectus  muscle  lies  to  the  outer  side  of  the  optic  nerve.  It  is 
attended  by  the  lachrymal  nerve,  a  branch  of  the  ophthalmic  nerve,  and  the 
lachrymal  artery,  a  branch  of  the  ophthalmic  artery.  You  will  dissect  the 
three  together  and  associate  them  in  your  memory.  The  lachrymal  structures 
are  on  their  way  to  the  lachrymal  gland.  Turn  the  external  rectus  muscle 


Tendon  of  superior  oblique 


Trochlea 


Internal  reotue 


Inferior  oblique  muscle 


Levator  palpebrae  super- 

ioris,  cut 
Superior  rectus 


External  rectus 


Inferior  rectu* 


FIG.  99. — LEFT  EYEBALL  SEEN  IN  ITS  NORMAL  POSITION  IN  THE  ORBIT,  WITH  VIEW  OF  THE 
OCULAR  MUSCLES.     (After  Merkel,  modified.) 


FIG.   loo.— MUSCLES  OF   ini.    \-.\\-..  TENDON  OR  LK;AMKM   OF  /INN. 
I.  Tendon  of  Zinn.     2.   External  rectus  divided.     3.   Internal  rectus.     4.  Inferior  rectus.      5.   Superior 
rectus.     6.  Superior  oblique.     7.    Pulley    for   superior  oblique.     8.    Inferior  oblique.     9.    Levator 
palpebrse  superioris.      10,  10.   Its  anterior  expansion.     II.  Optic  nerve. 


outward,  and  on  its  inner  surface  you  will  see  the  fine  filaments  of  the  sixth 
cranial  nerve — the  abducens. 

The  Superior  Oblique  Muscle  and  the  Fourth  Nerve  (Fig.  97). — These 
form  a  group  by  themselves.  You  will  trace  the  tendon  of  this  muscle  around 
the  trochlea,  where  it  turns  at  a  right  angle  and  passes  outward  under  the 


THE  HEAD  AND  NECK.  145 

superior  rectus  to  be  inserted  into  the  sclerotica.     You  will  find  its  nerve,  the  fourth, 
breaking  up  into  a  number  of  filaments  on  the  ocular  surface  of  the  muscle. 

The  nasal  nerve  crosses  the  optic  nerve,  passes  under  the  superior  rectus 
muscle,  then  passes  between  the  superior  oblique  muscle  and  the  internal  oblique 
muscle.  Here  it  gives  off  its  infratrochlear  branch  to  meet  the  supratrochlear 
branch  of  the  frontal  nerve.  These  two  are  sensory  nerves.  The  nerve  leaves 
the  orbit  by  the  anterior  ethmoid  foramen  with  the  anterior  ethmoidal  artery.  In 
the  cranial  cavity  it  lies  under  the  dura,  on  the  cribriform  plate  of  the  ethmoid 
bone.  It  passes  through  the  nasal  slit  to  the  nasal  fossae.  In  the  nasal  fossae  it 

Superior  reetus 
FOURTH  NERVE         \ 

Lsvator  palpsbree  superioris 

Lachrymal  and  frontal  vein  __SjM|K     (#^lL  f^~  SuPerior  oblique 

.0dfgeeovfAaPhenCoiUd8alfrflsnsuriebrOU8  ~              T^S*1^~  °PT1C  F°RA  ^'^  A*D  *Eli ' 'E 
Naso-ciliary  of  fifth  nerve jlS*$_^     ~  Internal  rectus 


SIXTH  NERVED  /  \ 

'  N  Inferior  reetus 

External  reotus       THIRD  NER  VE 

FIG.  101. — DIAGRAMMATIC  REPRESENTATION  OF  ORIGINS  OF  OCULAR  MUSCLES  AT  THE  APEX 

OF  THE  RIGHT  ORBIT. 
(After  Schwalbe,  slightly  altered.) 

divides  into  branches  :  (i)  Septal,  to  the  mucous  membrane  of  the  septum  ;  (2) 
turbinals,  to  the  turbinated  bones.  A  small  twig  from  the  latter  passes  between 
the  lower  end  of  the  nasal  bone  and  its  cartilage,  and  appears  on  the  face  as  the 
naso-lobular — a  nerve  of  sensation,  of  course,  to  the  wing  and  tip  of  the  nose. 

TABLE  OF  ORIGIN  OF  OCULAR  MUSCLES. 
NAME.  ORIGIN. 

Levator  palpebrae  superioris,    .  Above  optic  foramen  from  lesser  ala  of  sphenoid. 

Superior  rectus, Upper  margin  of  optic  foramen. 

Inferior  rectus,        From  ligament  of  Zinn. 

Internal  rectus, From  ligament  of  Zinn. 

External  rectus, Upper  head.     Outer  margin  of  optic  foramen. 

External  rectus, Lower  head.     From  ligament  of  Zinn. 

Superior  oblique, Above  the  optic  foramen. 

Inferior  oblique, Orbital  plate  of  superior  maxilla. 

The  internal  rectus  and  the  inferior  rectus  may  be  brought  into  view  by 
cutting  the  optic  nerve  and  pushing  the  eyeball  and  the  fatty  mass  forward. 
You  will  see  these  muscles  taking  their  nerve-supply  from  the  third  nerve. 
Trace  each  muscle  to  its  insertion  into  the  sclerotica. 

The  inferior  oblique  muscle  arises  from  the  orbital  plate  of  the  superior 
maxilla  just  external  to  the  lower  end  of  the  lachrymal  groove.  It  is  inserted 
into  the  sclerotica,  on  the  outer  surface,  in  such  a  way  as  to  antagonize  the 
superior  oblique  muscle.  Its  nerve,  the  long  branch  of  the  third  cranial,  is  of 
large  size,  and  gives  to. the  ciliary  ganglion  its  motor  root. 

The  orbital  fascia  invests  the  muscles.  It  passes  forward  on  the  tendons. 
In  the  vicinity  of  the  globe  it  binds  the  tendons  together  by  extending  from  one 
to  another,  thus  forming,  posterior  to  the  ball,  a  loose  double  capsule — the 
capsule  of  Tenon.  This  double  layer  forms  a  socket  for  the  ball  to  move  in.  It 
separates  posteriorly  the  fatty  contents  of  the  orbit  from  the  globe  of  the  eye. 

Describe  the  Ophthalmic  Artery  (Fig.  103). — It  is  a  branch  of  the  inter- 
nal carotid  artery.  It  enters  the  orbit  by  the  optic  foramen  with  the  optic  nerve. 
It  is  attended  by  the  ophthalmic  vein,  which  leaves  the  orbit  by  the  sphenoidal 


146 


SKIN  OF  LOWER  LID 
LOWER  TARSUS 
Palpebral   fascia   and 
aat.  lamina  of  muscle- 
fascia 

Orbicularis  palpe- 

brarum 

Intension  of  sheath  of 
inferior  root  us  to 
lower  eyelid 

FORNIX  CONJUNCTIV/C 


Inferior  oblique  mu3ol3, 
cut  across 


PERIORBITA 

Posterior  lamina  of 
muscle-fascia 


SUPRAVAGINAL    SPACE   CONTINUOUS 

WITH  TENON'S  SPACE 
SPACE  OCCUPIED  BY  ORBITAL  FAT,  PRO- 
CESSES OF  FASCIA  SEPARATING  THE 
LOBULES    AND    ENCLOSING     BLOOD- 
VESSELS 

Inferior  rectus 


PR  A  CTICAL  ANA  TO  MY. 
\ 


SKIN  OF  UPPER  LID 
UPPER  TARSUS 
CORNEA 

Orbicularis  palpe- 

brarum 

UPPER  RIM  OF  ORBIT,  WITH 
Splitting  of  periorbita 
Upper  or  anterior  insertion 

of  levator  palpebrae 
Superior  palpebral  muscle  of 
FORNIX  CONJUNCTIV/E        [Miiller 

Connection  between  levator 
palpebrae  and  sup.  reetus, 
and  fibres  to  conjunctiva 

PROCESS  FROM    PERIORBITA  TO 
CAPSULE  OF  LACHRYMAL  GLAND 


Superior  rectus 


Levator  palpebrae 
—  superioris 

Posterior  lamina  of  muscle- 
fascia  lined  by  prolongation  of 
Tenon's  capsule 

OPTIC  NERVE 


FIG.   102. — VERTICAL  SECTION  THROUGH  THE  EYEBALL  AND  ORBIT  IN  THE  DIRECTION  OF  THE 

ORBITAL  Axis,  WITH  CLOSED  EYELIDS. 

(Semi-diagrammatic.     After  Schwalbe,  modified  to  show  fasciae.) 
Periorbita  green  ;  muscle-fascia  red;  Tenon's  capsule  yellviv. 


Snpraorbital  artery 

LACHRYMAL  GLAND 

Superior  rectus,  cut 

EYEBALL 


External  rectus 
Lachrymal  artery  


Superior  rectus,  out 
Inferior  ophthalmic  vein 
Superior  ophthalmic  vein 


OPTIC  NKR  VI-: 
Common  ophthalmic  vein 


Commencement  o/  superior 
ophthalmic  vein 

Reflected  tendon  of  superior 

oblique 
Ophthalmic  artery 


Anterior  ethmoidal  artery 

Posterior  ethmoidal  artery 
Ciliary  arteries 

Levator  palpebrae,  cut 
Ligament  of  Zinn 
iiilmic  artery 


OPTIC  COMMISSURE 


Internal  carotid  artery 

FIG.  103. — TIIK  OPHTHALMIC  ARTKKV  AND  VEIN. 


THE   HEAD  AND  NECK.  147 

fissure   and  expands  behind  the  sphenoidal  fissure  to  form  the  cavernous  sinus. 
Its  branches  are  : 

1.  Lachrymal,  with  the  external  rectus,  sixth  nerve  to  lachrymal  gland. 

2.  Supraorbital,  with  the  frontal  nerve,  levator  palpebrae,  superior  rectus. 

3.  Arteria  centralis  retinas,  in  centre  of  optic  nerve  to  the  retina. 

4.  Anterior  ethmoidal,  with  the  nasal  nerve  to  ethmoid  cells. 

5.  Posterior  ethmoidal,  to  the  posterior  ethmoid  cells. 

6.  Palpebral  arteries,  to  the  upper  and  lower  lids. 

7.  Frontal  artery,  to  the  inner  angle  of  the  eye. 

8.  Nasal  artery,  to  the  lachrymal  sac  and  caruncula. 

9.  Muscular  branches,  to  the  muscles  of  the  eye. 
10.   Ciliary  arteries,  to  the  iris  and  choroid  coat. 
Hew  would  you  classify  the  nerves? 

1 .  Special  sense  :    The  optic  nerve — special  of  vision. 

(  Motor  :    Third,  to  all  except  two  muscles. 

2.  <  Motor  :    Fourth,  to  the  superior  oblique  muscle. 

(  Motor  :    Sixth,  to  the  external  rectus  muscle. 

T  Sensory  :    Nasal  branch  of  ophthalmic,  to  the  nose  and  orbit. 

3.  <  Sensory  :    Lachrymal  branch  of  ophthalmic,  to  lachrymal  gland. 

(  Sensory  :    Frontal  branch  of  ophthalmic,  to  forehead. 

4.  Sympathetic,  from  cavernous  plexus,  to  the  ciliary  ganglion. 


SUPERIOR  LACHRYMAL  GLAND 
INFERIOR  LACHRYMAL  GLAND 


DUCT  FROM  SUPERIOR  6LAND 


UPPER  EYELID  PARTIALLY 
DIVESTED  OF  SKIN 


UPPER  PUNCTUM 

LACHRYMAL  SAC,  NEAR  ITS  FUNDt'S 

COMMON  DUCT  FORMED  BY  JUNC- 
TION OF  CANALICULI 

UPPER  AND  LOWER  CANALICULI 
LOWER  PUNCTUM 


FIG.   104. — LACHRYMAL  APPARATUS.     (After  Schwalbe. ) 


The  lachrymal  gland  you  will  find  under  the  external  angular  process  of 
the  frontal  bone  in  the  lachrymal  fossa.  (Fig.  103.)  It  has  an  orbital  and  a 
palpebral  part,  a  capsule,  an  artery,  and  a  nerve. 

Define  the  periorbita  and  give  its  functions. 

This  is  the  orbital  periosteum.  It  forms  the  tarsal  ligaments  and  the  limbs  of 
the  inner  palpebral  ligament,  lines  the  floor  of  the  lachrymal  groove,  forms  the 
trochleafor  the  superior  oblique  muscle  of  the  eyeball,  assists  the  orbital  fascia  in 
forming  a  capsule  for  the  lachrymal  gland,  and  sustains  the  orbital  fat. 

Wliat  is  tJie  first  structiire  you  saw  on  removing  the  orbital  plate  of  the 
frontal  bone  ? 

The  periorbita  or  orbital  periosteum,  a  continuation  of  the  dura  mater 
through  the  sphenoidal  fissure  and  the  optic  foramen. 

On  removing  the  periorbita,  wliat  did  you  sec  f 

1.  In  the  middle  we  saw  the  frontal  artery,  a  branch  of  the  ophthalmic,  and 
the  frontal  nerve,  a  branch  of  the  ophthalmic  division  of  the  fifth  nerve,  lying  on 
the  levator  palpebrae  muscle. 

2.  To  the  outer  side  we  saw  the  lachrymal  artery,  a  branch  of  the  ophthalmic 


i4»  PRACTICAL  ANATOMY. 

artery,  and  the  lachrymal  nerve,  a  branch  of  the  ophthalmic  division  of  the  fifth 
nerve,  lying  on  the  external  rectus  muscle. 

3.  To  the  inner  side  we  saw  the  fourth  nerve,  called  also  the  patheticus, 
lying  on  and  supplying  the  superior  oblique  muscle  with  motion,  in  its  course 
having  passed  above  the  levator  palpebrae  muscle  and  the  frontal  nerve. 

Describe  the  frontal  nerve,  which  you  found  on  t/ie  levator  palpebrce,  and  tell 
what  structure  intervened  bet'cvcen  the  periorbita  and  this  nerve. 

The  intervening  structure  was  the  peripheral  part  of  the  orbital  fascia.  It  was 
so  thin  and  translucent  that  we  could  see  the  nerve  through  the  fascia.  The 
frontal  nerve  is  a  branch  of  the  ophthalmic  part  of  the  fifth  nerve.  About  midway 
between  the  optic  foramen  and  the  supraorbital  foramen  it  divides  into  a  supra- 
orbital  and  a  supratrochlear  branch.  The  supraorbital  branch  leaves  the  orbit 
through  the  supraorbital  foramen  and  supplies  the  skin  of  the  upper  lid,  the 
skin  of  the  forehead,  and  the  pericranium  in  this  same  region  ;  the  supratroch- 
lear branch  communicates  with  the  infratrochlear  branch  of  the  nasal  nerve 
around  the  pulley  for  the  superior  oblique  muscle,  branches  being  given  off 
from  this  loop  to  supply  the  upper  lid,  forehead,  and  nose. 

Describe  the  lachrymal  nerve,  which  you  saw  on  the  external  rectus  muscle. 

It  is  a  branch  of  the  ophthalmic  part  of  the  fifth  nerve.  It  gives  branches  to  the 
lachrymal  gland,  and  to  the  skin  and  mucous  membrane  of  the  upper  lid,  and  sends 
a  communicating  branch  to  the  orbital  branch  of  the  superior  maxillary  nerve. 

Describe  the  nasal  nerve. 

It  is  a  branch  of  the  ophthalmic.  It  has  a  most  complicated  course,  which 
to  be  learned  thoroughly  must  be  studied  according  to  these  stages  : 

1.  The  nerve  enters  the  orbital  cavity  by  the  sphenoidal  fissure. 

2.  In  its  course  through  the  orbit  it  passes  :  (i)  Between  the  optic  nerve  and 
superior  rectus  muscle ;  (2)  between  the  external  rectus  muscle  and  the  superior 
oblique   muscle,  and  arrives  at  the  anterior  ethmoidal  foramen.     In   this,   its 
orbital  stage,  the  nerve  gives  off  the  long  root  to  the  ciliary  ganglion,  at  the 
sphenoidal  fissure,  and  the  long  ciliary  nerves  to  the  eyeball,  as  it  crosses  the  optic 
nerve.     At  the  anterior  ethmoidal  foramen  the  nerve  gives  off  the  infratrochlear 
branch,  to  communicate  with  the  supratrochlear  branch  of  the  frontal  nerve. 

3.  In  company  with  the  anterior  ethmoidal  artery  it  enters  the  cranial  cavity, 
by  the  anterior  ethmoidal  foramen,  crosses  the   cribriform  plate  of  the  ethmoid 
bone,  and  leaves  the  cranial  cavity  and  gains  the  nasal  cavity  by  the  nasal  slit,  by 
the  side  of  the  crista  galli. 

4.  The  nerve  divides  in  the  nasal  cavity  into  septal  branches,  which  are  dis- 
tributed to  the  upper  and  front  part  of  the  septum  nasi,  and  branches  to  the 
outer  wall  and  anterior  ends  of  the  two  lower  turbinals.     The  end  branch  of  this 
nerve  passes  between  the  cartilage  and  the  end  of  the  nasal  bone,  supplying  the 
tip  and  lobe  of  the  nose. 

Describe  the  motor  oculi,  or  third  cranial  nerve. 

This  nerve  is  the  most  important  motor  nerve  to  the  muscles  of  the  orbit. 
As  the  nerve  emerges  from  the  cavernous  sinus  it  divides  into  a  superior  and 
an  inferior  division,  which  enter  the  orbit  by  the  sphenoidal  fissure.  The 
superior  division  supplies  the  levator  palpebrae  and  superior  rectus  muscles. 
The  inferior  division  supplies  the  internal  rectus,  the  inferior  rectus,  and  the 
inferior  oblique.  The  third  nerve  supplies  with  motion  the  circular  fibres  of  the 
iris  and  the  ciliary  muscle,  through  the  ciliary  ganglion. 

Describe  the  fourth  crania!  nerve. 

It  is  called  patheticus  and  trochlear.  It  enters  the  orbit  by  the  sphenoidal 
fissure,  passes  above  the  frontal  nerve  and  levator  palpebras  muscle,  and  is 
distributed  to  the  superior  oblique  muscle.  This  is  the  smallest  of  the  cranial 
nerves. 


THE  HEAD  AND  NECK.  149 

Describe  the  sixth  cranial  nerve. 

It  is  called  the  abducent  nerve.  It  enters  the  orbit  by  the  sphenoidal  fissure, 
between  the  two  heads  of  the  external  rectus,  to  which  muscle  it  is  distributed. 

Describe  the  optic  nerve. 

This  is  the  nerve  of  the  special  sense  of  sight.  It  is  the  second  cranial  nerve. 
It  enters  the  orbit  by  the  optic  foramen,  internal  to  and  above  the  ophthalmic 
artery.  It  pierces  the  ball  of  the  eye  and  forms  the  retina.  It  is  surrounded  by 
the  ciliary  vessels  and  nerves.  To  its  outer  side  is  the  ciliary  ganglion.  At  the 
optic  foramen  it  is  surrounded  by  the  four  recti  muscles.  The  arteria  centralis 
retinae  pierces  its  under  surface  and  goes  to  the  interior  of  the  eyeball.  The 
process  of  dura  that  surrounds  the  nerve  divides  in  such  a  manner  as  to  form  a 
sheath  for  the  nerve,  and  also  the  orbital  periosteum,  inside  the  orbit.  The 
optic  sheath  is  continuous  with  the  sclerotica. 

Wliat  is  the  orbital  fascia? 

It  is  a  variety  of  connective  tissue,  being  to  the  contents  of  the  orbit  what 
the  deep  fascia  is  to  the  thigh.  It  forms  a  capsule,  in  conjunction  with  the  peri- 
orbita,  for  the  lachrymal  gland,  and  sheaths  for  the  muscles,  vessels,  and  nerves. 
It  is  connected  to  the  ocular  conjunctiva  close  to  the  cornea.  The  muscular 
sheaths  are  firmly  adherent  to  the  muscles.  The  insertions  of  the  ocular  muscles 
into  the  sclerotica  are  connected  together  around  the  whole  circumference  of 
the  globe.  From  this  attachment  this  fascial  connecting  medium  is  reflected 
backward  in  a  double  layer,  forming  the  fibrous  basis  of  a  serous  membrane — 
the  visceral  layer  covering  the  back  part  of  the  globe,  the  parietal  lining  the 
postocular  fat  in  the  orbit.  A  layer  of  endothelial  cells  completes  the  serous 
membrane.  Here  we  have  a  visceral  layer,  a  cavity,  and  a  parietal  layer,  the 
three  cardinal  points  in  any  serous  apparatus.  This  reflected  part  of  the  orbital 
fascia  permits  free  movement  of  the  eyeball,  as  the  head  of  a  bone  revolves  in  its 
socket,  and  is  known  in  anatomy  as  the  capsule  of  Tenon. 

By  what  is  the  orbital  fascia  on  the  posterior  part  of  the  eyeball  pierced  ? 

It  is  pierced  by  the  vessels  and  nerves  that  supply  the  globe. 

What  muscle  did  you  find  immediately  under  the  levator  palpebrce  ? 

The  superior  rectus,  and  under  this  we  found  the  optic  nerve,  surrounded  by 
fat,  vessels,  and  nerves. 

Name  the  muscles  of  the  eyeball  and  give  their  function. 

The  external  rectus  abducts  the  cornea. 

The  internal  rectus  adducts  the  cornea. 

The  superior  rectus  elevates,  adducts,  and  rotates  cornea  inward. 

The  inferior  rectus  depresses,  adducts,  and  rotates  cornea  outward. 

The  superior  oblique  depresses,  abducts,  and  rotates  cornea  inward. 

The  inferior  oblique  elevates,  abducts,  and  rotates  cornea  outward. 

The  levator  palpebrae  elevates  the  upper  eyelid. 

Name  all  the  nerves  that  supply  the  orbital  contents. 

The  optic,  the  nerve  of  special  sense  of  sight. 

The  motor  oculi,  a  motor  nerve  to  all  muscles  except  two. 

The  pathetic,  a  motor  nerve  to  the  superior  oblique  muscle. 

The  abducens,  a  motor  nerve  to  the  external  rectus  muscle. 

The  frontal,  a  branch  of  the  ophthalmic  of  the  fifth  nerve. 

The  lachrymal,  a  branch  of  the  ophthalmic  of  the  fifth  nerve. 

The  supratrochlear  branch  of  the  frontal. 

The  palpebral  branches  of  the  frontal. 

The  infratrochlear  branch  of  the  nasal. 

The  long  ciliary  branches  of  the  nasal. 

The  short  ciliary  branches  of  the  lenticular  ganglion. 

The  cavernous  sympathetic  branches  to  lenticular  ganglion. 


150  PRACTICAL    ANATOMY. 

The  lenticular  or  ciliary  ganglion. 

\VIiere  is  tlic  ciliary  ganglion  located,  and  how  is  it  formed .' 

It  lies  between  the  external  rectus  muscle  and  the  optic  nerve  on  the  outer 

side  of  the  ophthalmic  artery.      It  is   the    size    of  a  pin's  head.      It   has   three 

roots  : 

1 .  A  sensory  root  from  the  nasal  nerve. 

2.  A  motor  root  from  the  motor  oculi  nerve. 

3.  A  sympathetic  root  from  the  cavernous  sympathetic. 
Hoiv  do  the  nerves  gain  access  to  the  orbit  ? 

The  optic  nerve  passes  through  the  optic  foramen  ;  all  the  others  pass  through 
the  sphenoidal  fissure  with  the  ophthalmic  vein. 

Name  all  the  structures  seen  on  inspecting  the  eye  of  a  patient. 

1.  The  palpebral  fissure,  a  slit  between  the  lids. 

2.  The  outer  and  inner  canthi,  the  extremities  of  the  fissure. 

3.  The  tarsal  cartilages,  the  free  margins  of  the  lids. 

4.  The  cornea,  behind,  which  is  the  iris. 

5.  The  pupil,  surrounded  by  the  iris.- 

6.  The  tendo  oculi,  or  inner  palpebral  ligament. 

7.  The  lachrymal  caruncle,  just  within  the  inner  can  thus. 

8.  The  superior  palpebral  fold  when  the  eye  is  opened. 

9.  The  inferior  palpebral  fold  when  the  eye  is  opened. 
10.  The  palpebral  and  ocular  conjunctivae. 

i  i.  The  conjunctival  cul-de-sac  or  fornix. 

1 2.  The  sclerotica,  or  white  of  the  eye. 

13.  The  conjunctival  sac.     This  is  the  space  between  the  posterior  surface  of 
the  lid  and  the  eyeball.     It  is  completely  covered  by  conjunctiva. 

A  patient  gets  a  cinder  in  his  eye :  What  nerve  or  nerves  report  the  pain  to  the 
brain  f 

The  cornea  and  sclerotica  are  supplied  by  the  ciliary  nerves.  The  infra- 
trochlear  branch  of  the  nasal  nerve  supplies  the  conjunctiva,  the  lachrymal  sac, 
and  the  caruncula  lachrymalis.  The  lachrymal  nerve  sends  conjunctival  branches 
to  the  upper  lid.  The  palpebral  branches  of  the  superior  maxillary  send  con- 
junctival branches  to  the  lower  lid.  While,  then,  a  number  of  branches  are  con- 
cerned locally,  one  nerve,  the  trigeminus  or  fifth,  does  terminal  work  for  all, 
since  the  lachrymal,  nasal,  superior  maxillary,  and  the  sensory  root  of  the  ciliary 
ganglion  are  all  derived  from  the  fifth  nerve.  A  reflex  circuit  is  completed  by 
the  seventh  nerve,  acting  on  the  orbicularis  palpebrarum  to  close  the  eye. 

Emissary  Foramina  and  Their  Veins. — 

Define  emissary  foramina  ami  emissary  veins. 

Emissary  foramina  derive  their  importance  from  the  veins  they  transmit ; 
emissary  veins  are  both  physiologically  and  pathologically  important.  The  emis- 
sary veins  are  connected  centrally  to  the  sinuses  in  the  dura  mater ;  peripherally 
they  communicate  with  veins  both  deep  and  superficial.  From  a  physiological 
standpoint  these  veins  regulate  indirectly  the  arterial  pressure  in  the  brain,  since, 
in  cases  of  cerebral  engorgement,  when  the  internal  jugular  veins  are  unable  to 
convey  the  required  amount  of  blood  in  the  dural  sinuses  from  the  brain,  the 
emissary  veins  deliver  large  quantities  of  this  venous  blood  to  the  superficial  or 
to  the  deep  veins  with  which  they  communicate  peripherally.  This  action  of  the 
emissary  veins  has  been  compared  to  a  safety-valve  in  mechanics.  From  a 
pathological  standpoint  these  veins  are  conveyers  of  septic  material  from  areas 
accessible  to  the  surgeon  and  physician,  to  regions  beyond  the  reach  of  either. 
Infection  in  the  orbit,  posterior  nares,  and  scalp  over  the  forehead  reaches  the 
cavernous  sinus  via  the  angular  and  ophthalmic  veins.  Infection  in  the  face, 
nose,  and  teeth  reaches  the  cavernous  sinus  via  the  Vesalian  vein  and  pterygoid 


THE  HEAD  AND  NECK.  151 

plexus.  The  conservatism  of  emissary  veins  is  well  illustrated  in  the  profuse 
epistaxis  of  children,  incident  to  cerebral  congestion.  In  this  case  an  emissary 
vein  connects  centrally  the  blood  in  the  superior  longitudinal  sinus  with  the 
blood  in  the  mucous  membrane  of  the  nose  ;  the  latter,  being  the  weaker  structure, 
gives  way,  and  the  arterial  pressure  in  the  brain  is  relieved  by  a  profuse  hemor- 
rhage. The  emissary  foramina  seem  to  belong  more  especially  to  the  physio- 
logical needs  of  childhood.  .The  greater  number  of  emissary  veins  and  their 
foramina  disappear  as  adult  years  come  on.  By  osteological  classification  these 
foramina  are  inconstant. 

The  following  table  gives  a  list  of  the  emissary  foramina,  the  central  sinuses, 
and  the  peripheral  veins,  between  which  the  emissary  veins  stand,  holding  the 
two  together  like  the  handle  connects  the  two  globes  of  a  dumb-bell  : 

TABULATED  LIST  OF  EMISSARY  STRUCTURES. 

FORAMEN.  CENTRAL  SINUS.  PERIPHERAL  VEIN. 

Caecum Superior  longitudinal,  Nasal  mucous  membrane. 

Carotid  canal, Cavernous,  Internal  jugular  vein. 

Parietal, Lateral,  Occipital. 

Vesalii, Cavernous,  Internal  jugular  vein. 

Posterior  condylar, Lateral,  Deep  cervical. 

Occipital, Torcular  Herophili,  Occipital  veins. 

Anterior  condylar Occipital,  Deep  cervical. 

Mastoid, Lateral,  Occipital  veins. 

Sphenoidal  fissure Cavernous,  Angular  and  ophthalmic. 

Ovale Cavernous,  Pharyngeal  and  pterygoid. 


How  SEPTIC  THROMBI   REACH   THE  SINUSES. 

How  may  a  carbuncle  of  tJie  face,  or  facial  erysipelas,  or  infection  of  tJie  scalp 
over  the  forehead  result  in  fatal  blood-poisoning  ? 

Septic  thrombi  from  these  sources-  may  reach  the  cavernous  sinus  and  get 
beyond  the  reach  of  the  surgeon.  The  frontal  and  supraorbital  veins  unite  to 
form  the  angular,  and  this  is  one  of  the  large  tributaries  of  the  facial  vein. 
(Fig.  1 8.)  Now,  the  angular  vein  communicates  with  the  ophthalmic.  The 
ophthalmic  vein  passes  through  the  sphenoidal  fissure,  and  is  tributary  to  the 
cavernous  sinus.  The  angular,  facial,  and  ophthalmic  veins  contain  no  valves, 
hence  the  blood  can  pass  either  forward  or  backward  from  the  superficial  seat  of 
infection  to  a  region  beyond  the  reach  of  surgical  drainage  and  antisepsis. 

Tell  the  course  septic  material  from  a  carious  tooth,  alveolar  abscess,  or  suppura- 
tion of  the  antrum  folloius  in  cases  of  fatal  blood-poisoning-  to  reach  the  sinuses  in 
the  dura  mater  beyond  the  reacli  of  operative  procedure. 

To  appreciate  an  answer  to  this  question  you  must  recall  the  distribution  of  the 
internal  maxillary  artery  to  the  muscles  of  mastication,  the  teeth,  the  nasal  fossae, 
the  meninges,  and  the  palate.  Now,  the  veins  returning  the  blood  from  these  areas 
take  the  course  of  their  companion  arteries,  and  the  same  name  as  the  arteries. 
The  veins  from  these  regions,  the  small  and  great  meningeal,  the  supraorbital 
and  posterior  dental,  the  palatine  and  spheno-palatine,  the  deep  temporal,  ptery- 
goid, and  buccal,  the  lower  ophthalmic  and  Vesalian,  all  come  together  on  the 
inner  surface  of  the  internal  pterygoid  muscle  to  form  the  pterygoid  plexus. 
This  plexus  communicates  with  the  cavernous  sinus  by  the  Vesalian  vein.  As 
these  veins  contain  no  valves,  septic  thrombi  originating  anywhere  in  the  dental, 
alveolar,  antral,  nasal,  or  palatine  regions  may  spread  backward  to  the  cavernous 
sinus  via  the  Vesalian  vein  and  pterygoid  plexus. 


SHOULDER,  ARM,  FOREARM,  AND  HAND. 


I  prefer  to  have  my  students  begin  a  dissection  of  the  upper  extremity  on 
the  fingers  and  hand.  The  liability  of  these  parts  to  become  dry,  to  say  nothing 
of  the  great  practical  importance  of  this  region,  is  sufficient  apology.  Any  dis- 
section of  the  hand  without  a  review  of  the  salient  osteological  landmarks  will 
be,  in  a  measure,  a  poor  dissection,  unsatisfactory  alike  to  teacher  and  student. 
The  student  should  become  master  of  the  following  points  in  osteology  before 
he  begins  work  on  the  cadaver : 


OSTEOLOGICAL   POINTS    ON   THE    HAND. 

The  Carpus  and  Hand  (Figs.  108  and  109). 

Name  the  points  on  the  bones  of  the  carpus  and  hand  of  importance  in  practical 
anatomy. 

The  carpo-metacarpal  articulations. 

The  base  of  the  first  or  thumb  metacarpal. 

The  base  of  the  second  metacarpal,  radial  side. 

The  base  of  the  third  metacarpal,  radial  side. 

The  base  of  the  fifth  metacarpal,  ulnar  side. 

The  pisiform  bone  of  the  carpus. 

The  groove  in  the  os  trapezium. 

The  unciform  process  of  the  unciform  bone. 

The  base  of  the  first  thumb  phalanx. 

The  base  of  the  second  thumb  phalanx. 

The  dorsal  bases  of  index,  middle,  and  ring  fingers. 

The  dorsal  bases  of  second  and  third  phalanges. 

The  palmar  bases  of  second  and  third  phalanges. 

What  is  the  importance  of  the  groove  in  the  os  trapezium  at  the  base  of  the 
thumb  f 

It  transmits  the  tendon  of  the  flexor  carpi  radialis  to  its  insertion  into  the 
base  of  the  index  metacarpal  bone. 

What  is  the  importance  of  the  base  of  the  fifth  metacarpal  ? 

On  its  palmar  side  is  inserted  the  flexor  carpi  ulnaris  ;  on  its  dorsal  the  ex- 
tensor carpi  ulnaris.  These  muscles  are  antagonized  by  radial  and  ulnar  carpal 
extensors. 

Name  the  radial  and  ulnar  extetisors  of  tJie  carpus. 

There  are  two  radial  extensors  of  the  carpus  :  the  extensor  carpi  radialis 
longior  and  brevior,  inserted  into  the  bases  of  the  second  and  third  metacarpals 
respectively,  on  the  radial  side.  The  extensor  carpi  ulnaris  is  inserted  into  the 
base  of  the  fifth  metacarpal  on  the  ulnar  side. 

Give  the  importance  of  the  pisiform  bone  and  the  unciform  process  of  the  unciform 
bone  on  the  ulnar  side  of  the  carpus,  in  conjunction  ~^ilh  t/ic  scaphoid  and  trapezium 
on  the  radial  side. 

It  is  these  bones  that  give  attachment  to  the  anterior  annular  ligament  of  tlu- 

152 


SHOULDER,  ARM,  FOREARM,  AND   HAND. 


153 


wrist,  a  band  of  deep  fascia  that  binds  down  the  strong  flexor  tendons  of  the 
fingers  and  thumb,  and  also  preserves  the  transverse  carpal  arch. 


Pectoralis  major,  hooked  up 


External  jugular  vein 


Pectoralis  major 


Lymphatics  from  side  of  chest 


Pectoral  glands 


Basilic  vein 


ven  —r, 

Epitrochlear  gland  —1 
ial  ulnar    ' 


Posterior  superficia 

vein 

Median  basilic  vein 
Inner  set  of  superficial  lym- 
phatics of  forearm 

Deep  median  vein  — 

INTERNA  L  CUTA  NEO  US 
NER  VE 

Anterior  superficial  ulnar 
vein 

Median  set  of  superficial  lym- 
phatics of  forearm 


Supraclavicular  gland 
Jugulo-cephalic  vein 

Deltoid  muscle 


Lymphatics  accompanying 
cephalic  vein 

Axillary  glands 


Cephalic  vein 


Lymphatic  vessels  of  inner 
side  of  arm 


Biceps,  exposed 

MUSCULO-CUTANEO  US 
NER  VE 

Brachial  artery 
Bicipital  fascia 
Median  cephalic  vein 

Superficial  radial  vein 
Superficial  median  vein 


Outer  set  of  superficial  lym- 
phatic vessels  of  forearm 


FIG.  105. — SUPERFICIAL  VEINS  AND  LYMPHATICS  OF  THE  FOREARM  AND  ARM. 

What  is  on  the  palmar  surface  of  the  phalanges  ? 

A  groove  limited  laterally  by  a  ridge  of  bone  on  each  side.     The  groove  is 
converted  into  an  osseo-aponeurotic  canal  by  a  strong  covering  of  deep  digital 


154 


fascia,  called  the  ligamentum  vaginale.      In  this  canal  are  found  the  flexor  ten- 
dons, invested  by  a  synovia!  membrane  called  theca. 

ANTERIOR  PART. 

Locate  on  the  cadaver  :  (i)  The  clavicle  ;  (2)  the  sternum  ;  (3)  sterno-clavicu- 
lar  articulation  ;  (4)  acromio-clavicular  articulation  ;  (5)  the  acromion  ;  (6)  the 
coracoid  process  ;  (7)  the  greater  tuberosity  of  the  humerus  ;  (8)  the  lesser 
tuberosity  of  the  humerus ;  (9)  the  internal  condyle  ;  (10)  the  external  condyle  ; 
(i  i)  the  radial  head  5(12)  the  clefts  of  the  fingers  ;•  (13)  the  thenar  eminence  ; 


INTERNAL 
CUTANEOUS  OF 
MUSCULO- 
SPIRAL 


INTERNAL 
CUTANEOUS 


PALMAR 

CUTANEOUS  OF 

MEDIAN 
PALMAR 

CUTANEOUS  OF 

ULNAR 


SUPRA- 

ACROMIAL 


CIRCUMFLEX 


INTERCOSTO- 
HUMERAL 


TWIG  OF 
INTERNAL 

CUTANEOUS 


CIRCUM-\ 
FLEX  1 


EXTERNAL 
CUTANEOUS  OF 

MUSCULO- 

SPIRAL 


MUSCULO- 
CUTANEOUS 


EXTF.RNAL 
CUTANEOUS 

OF 

MUSCULO- 
SPIRAL 


MUSCULO- 
CUTANEOU* 


RADIAL 


PALMAR 
CUTANEOUS 
OF  RADIAL 


SUPRA- 
ACROMIAL 


INTERNAL 

crrTA\EOUS  OF 

MUSCULO- 
SPIRAL 
INTERCOSTO- 
HL'MERAL 


NERVE  OF 
WRISBERQ 


INTERNA  L 
CUTANEOUS 


ULNAR 


FIG.   106. — DISTRIBUTION  OF  CUTANEOUS  NERVES  ON  THE  ANTERIOR  AND  POSTERIOR  .Asn-rrs 

OF  THE  SUPERIOR  EXTREMITY. 


(14)  the  hypothenar  eminence;  (15)  the  metacarpo-phalangeal  articulation; 
(16)  the  phalangeal  articulations;  (17)  the  pisiform;  (18)  the  unciform  pro- 
cess of  the  unciform  bone. 

Incisions. — (i)  From  the  acromion  to  the  end  of  the  middle  finger ;  (-2)  from 
the  sterno-clavicular  articulation  to  the  acromion  ;  (3)  from  condyle  to  condyle  ; 
(4  through  the  metacarpo-phalangeal  crease. 

NOTE. — In  making  these  incisions  care  must  be  taken  not  to  cut  too  deeply, 
in  order  to  avoid  doing  violence  to  the  cutaneous  vessels  and  nerves.  Now 
remove  the  skin  very  carefully  and  expose  the  following  cutaneous  nerves  and 
veins  : 

I.   The  ccpJialic  vein — a  continuation  of  the  radial  above  the  elbow.   (Fig.  105.) 


SHOULDER,  ARM,  FOREARM,  AND   HAND. 


155 


2.  The  basilic  vein — a  continuation  of  the  ulnar  above  the  elbow. 

3.  The  superficial  radial  vein,  on  radial  side  of  forearm. 

4.  The  superficial  median  vein,  on  midfront  of  forearm. 

5.  The  anterior  superficial  nlnar  vein,  on  ulnar  side  of  forearm. 

6.  The  posterior  superficial  ulnar  vein,  on  posterior  part  of  forearm. 

7.  The  deep  median  vein,  a  communicating  vessel. 

8.  The  external  jugular  vein,  seen  above  the  clavicle. 

Cutaneous  Nerves. 

1.  The  palmar  cutaneous  branch  of  the  ulnar  nerve,  supplying  1.5  fingers. 

2.  The  palmar  cutaneous  branch  of  the  median  nerve,  supplying  3.5  fingers. 

3.  The  palmar  cutaneous  branch  of  the  radial  nerve,  to  ball  of  thumb. 


THnar  portion  of  palmar  bursa 
Radial  portion  of  palmar  buraa 


Anterior  annular  ligament 


Lumbricalis 


Deep  transverse 
ligament 


Superficial  transverse  ligament 


FIG.  107. — DIAGRAM  OF  THE  GREAT  PALMAR  BURSA. 


4.,  The  cutaneous  branch  of  the  musculo-cutaneous  nerve. 

5.  The  internal  cutaneous  nerve  on  internal  part  of  the  forearm. 

6.  The  intercosto-humeral  nerve  on  internal  part  of  the  arm. 

7.  The  cutaneous  brancJi  of 'the  circumflex  nerve  over  insertion  of  deltoid. 

8.  The  internal  cutaneous  branch  of  the  muscido-spiral  nerve. 

Directions  for  Dissecting  the  Cutaneous  Vessels  and  Nerves. — Consult  figures 
105  and  1 06.  Plow  through  the  upper  fat-bearing  strata  of  the  superficial  fascia 
with  the  forceps — never  with  the  scalpel.  You  will  find  all  the  vessels  and 
nerves  in  the  deep  layer  of  the  superficial  fascia.  Divide  the  fascia  in  the  direction 
of  the  vessels  and  nerves. 

The  radial  veins  converge  to  form  the   cephalic  vein    above    the  elbow. 


156 


PRACTICAL    ANATOMY. 


(Fig.  105.)  The  ulnars  converge  to  form  the  basilic  vein  above  the  elbow. 
The  medians  converge  to  form  one  large  vein.  This  vein  breaks  up  into  the 
median  ccpJialic  and  median  basilic,  which  join  respectively  the  cephalic  and 
basilic  veins.  (Fig.  105.) 

Observe  that  the  internal  cutaneous  nerve  passes  behind  the  median  basilic 
vein  ;  that  the  cutaneous  branch  of  the  musculo-cutaneous  nerve  passes  behind  the 
median  cephalic  vein.  (Fig.  105.) 

Find  the  deep  median  vein,  piercing  the  deep  fascia  near  the  bifurcation  of 


SEMILUNAR 


ISIFORM 
EIFORM 


Extensor  carpi 
radialis  longior 

Extensor  carpi 
radialia  brevier 


Extensor  carpi  ulnarii 


Extensor  oommunis  digitorum 


Extensor  oommunis  digitorum 
THIRD,  UNGUAL,  OR  TERMINAL  PHALANX 


FIG.   108. — THE  LEFT  HAND.     (Dorsal  surface.) 


the  superficial  median  vein.     Trace  it  to  the  ulnar  vein  below  the  deep  fascia. 
(Fig.  105.) 

Note  that  the  median  basilic  vein  crosses  the  lower  part  of  the  bracliial 
artery.  Notice  also  the  bicipital  fascia  between  these  two  structures.  (Fig. 
105.)  This  vein  was  formerly  a  favorite  in  bleeding.  The  basilic  vein  termin- 
ates in  the  axillary  ;  the  cephalic  in  the  axillary  vein  also.  Find  the  cephalic 
vein  in  a  groove  between  the  pectoralis  major  and  deltoid  muscles  with  the 
'Irscending  branch  of  the  acromio-thoracic  artery  below  the  clavicle. 


SHOULDER,  ARM,  FOREARM,  AND   HAND. 


157 


The  cutaneous  branch  of  the  musculo-cutaneous  nerve  supplies  the  skin  over 
the  insertion  of  the  biceps  ;  inasmuch  as  the  supinator  longus  is  also  a  flexor  of 
the  forearm,  and  receives  a  part  of  its  nerve-supply  from  the  musculo-cutaneous 
nerve,  the  skin  over  the  insertion  of  this  muscle  is  also  supplied  by  the  same 
nerve.  See  Hilton's  law  in  the  introductory  chapter. 


Plexor  brevis 

pullieia 


Abductor  pollicis 


Flexor  carpi  ulnaris 
Abductor  minimi 
digiti 

Flexor  brevis  and 
opponens  minimi 
digiti 

Flexor  carpi 
ulnaris 


Adductor  pollicis 


Opponens  minimi 

digiti 


Abductor  and 
flexor  brevis 
minimi  digiti 


Opponens  pollicis 

Occasional  insertion  into  trapezium 
Extensor  oasis  metacarpi  pollicis 

Flexor  carpi  radialis 
Interosseus  primus  volaris 
•   Opponens  pollicis 


Flexor  brevis  and 
Abductor  pollicis 

Flexor  brevis  and 
Adductor  pollicis 


Flexor  longua 
pollicis 


Flexor  sublimis  digitorum 


Flexor  profundus  digitorum 


FIG.   109. — THE  LEFT  HAND.     (Palmar  surface.} 


DEEP  FASCIA  OF   THE  HAND. 

The  deep  fascia — fascia  profunda — lies  immediately  under  the  superficial 
fascia,  being  in  intimate  trabecular  relation  with  the  deep  layer  of  the  superficial 
fascia.  In  the  palm  of  the  hand  it  is  very  dense  and  heavy  ;  over  the  thenar  and 
hypothenar  eminences  it  is  very  thin. 

The  deep  fascia  takes  the  following  special  names  : 

1.  The  anterior  annular  ligament — in  front  of  wrist. 

2.  The  palmar  fascia — in  palm  of  the  hand. 

3.  The  ligamenta  vaginales — on  flexor  side  of  the  digits. 


158 


PRACTICAL   ANATOMY. 


4.  Internal  and  external  intermuscular  fascia. 

5.  The  posterior  annular  ligament. 

6.  The  dorsal  fascia  of  the  hand. 


Flexor  carpi  radialis 


Flexor 
carpi  ulnaris 


Deep  fascia  of 
forearm 


Extensor  oasis  metacarpi  pollicis 

^ Opponens  pollicis 

Abductor  pollicis 

Flexor  brevis  pollicis 
Adductor  Follicle 


First  lum- 

bricalis 
-  First  dorsal 
interos- 

seoua 


Iiigamentum  vaginale 

Flexor  sublimis  digitorum 


Flexor  profundua  digitorum 


Flexor  profundus 
digitorum 


FIG.  no. — THE  SUPERFICIAL  MUSCLES  OK  THE  PALM  OK  THE  HAND. 

Dissection  of  the  Jiand — in  which  find  the  following  : 

1.  The  palmar  fascia  and  palmaris  brevis  muscle. 

2.  The  flexor  tendons  and  their  sheaths  and  vincula. 

3.  The  digital  nerves  and  arteries  and  digital  veins. 

4.  The  superficial  palmar  arch  and  its  branches  on  flexor  tendons. 

5.  The  thecal  culs-de-sac,  synovial  in  the  ligamenta  va;^inalis. 


SHOULDER,  ARM,  FOREARM,  AND   HAND. 


*59 


6.  The  anterior  annular  ligament  on  front  of  carpus. 

7.  The  musculi  lumbricales  on  flexor  tendons. 

8.  The  thenar  and  hypothenar  muscles  about  thumb  and  little  finger. 

9.  The  deep  palmar  arch  and  branches  below  the  flexor  tendons. 

10.  The  deep  palmar  branch  of  the  ulnar  nerve  with  deep  arch. 

1 1.  The  dorsal  interossei  muscles. 

12.  The  ulnar  nerve  in  the  hand,  supplying  1.5  fingers. 

13.  Deep  palmar  arch  and  branches  of  ulnar  nerve  in  the  hand. 

14.  The  median  nerve  in  the  hand,  supplying  3.5  fingers. 

15.  The  radial  and  ulnar  arteries  in  the  hand,  forming  the  arches. 

1 6.  The  palmar  interosseous  muscles  on  the  palmar  surface. 

Dissection. — The  palmar  fascia  is  the  deep  fascia  of  the  flexor  surface  of  the 


MEDIAN  NERVE 


BRANCH  TO  MUSCLES 
OF  THUMB 


COLL A TERAL 
BRANCHES  OF 
MEDIAN 


ULNAR  NERVE 


COMMUNICA  TION 
BETWEEN  MEDIAN 
AND  ULNAR 


COLLATERAL 
BRANCHES  OF 
ULNAR 


FIG.   in. — SUPERFICIAL  NERVES  OF  'IHE  PALM.     (Ellis.) 

hand  from  the  annular  ligament  above  to  the  clefts  of  the  fingers  below.  Having 
removed  the  skin  of  the  palm,  and  noticed  the  granular  fat  in  the  superficial 
fascia  thereof,  you  are  now  ready  to  study  the  palmar  fascia.  This  fascia  has 
three  divisions  :  (i)  An  inner  thin  part  that  covers  the  muscles  forming  the  ball 
of  the  little  finger  ;  (2)  an  outer  thin  part  that  covers  the  muscles  forming  the 
bail  of  the  thumb  ;  (3)  a  central  strong  portion,  investing  the  central  distributory 
region  of  the  hand,  in  such  a  way  as  to  protect  the  vessels  and  nerves  for  the 
supply  of  the  fingers  and  adjacent  structures.  The  palmar  fascia  is  continuous 
above  with  the  anterior  annular  ligament,  and  below  with  the  ligamenta  vaginales 
in  the  form  of  heavy  protective  sheaths  for  the  flexor  tendons  of  all  the  fingers. 
Figure  1 10  shows  this  ligamentum  vaginale  still  intact  in  the  little  finger. 

The  Flexor  Tendons   and  Ligamenta  Vaginales. — Cut  through  the  very 


i6o 


PRACTICAL  ANATOMY. 


centre  of  the  dense  ligaincnta  vagitialcs  and  you  will  come  down  on  the  two 
flexor  tendons.  Notice  that  the  tendon  of  the  flexor  profnndus  digitontui  passes 
through  a  slit  in  the  tendon  of  the  flexor  snbliinis  digitornin.  (Fig.  1 10.)  The 
former  is  inserted  into  the  base  of  the  third,  the  latter  into  the  base  and  sides  of 
the  second  phalanx.  Now  gently  separate  these  tendons  and  you  will  see  (i) 
the  visceral  layer  of  synovial  membrane  on  the  tendons,  and  (2)  the  vincula — 
delicate  tendinous  cords. 


Flexor  carpi 
ulnaria 


Abductor  minimi 
digiti 


Flexor  sublimis 
digitorum 


Flexor  brevis 
minimi  digiti 


Flexor  prot'undus 
digitorum 


Extensor  oasis  metacarpi  pollicis 
Flexor  carpi  radialis 
Extensor  brevis  pollicis 

Abductor  pollicis 


Opponens  pollicis 


Abductor 
pollicis 
Flexor  brevis 
pollicis 


FIG.   112. — THE  DEEPER  MUSCLES  OK  THE  PALM  OK  THE  HAND. 


These  heavy,  deep  fascial  sheaths  you  have  just  cut  through  are  lined  by 
synovial  vaginal  membrane  called  the  theca.    In  the  thumb  and  little  finger  these 
synovial  cavities  communicate  with  the  ulnar  and  radial  palmar  bursae  above  the 
annular  ligament.     (Fig.  107.) 

The  thecre  for  the  remaining  fingers  terminate  in  thecal  culs-de-sac  opposite 
the  metacarpo-phalangeal  articulations.     (Fig.  107.) 

Infection   in   the   thumb  and   little   finger  thus  is  liable  to  travel   beyond  the 
annular  ligament,  while  in  the  other  fingers  it  would  be  arrested  at  the  culs-de-sac. 


SHOULDER,   ARM,  FOREARM,  AND  HAND, 


161 


A  case  of  unusual  interest,  bearing  on  this  point,  reported  by  Dr.  David  Loring, 
of  Valparaiso,  Indiana,  is  as  follows  :  "  Infection  ensued  where  a  patient  thrust  a 
nail  through  the  anterior  annular  ligament.  One  by  one  all  the  carpal  bones,  the 
bones  of  the  thumb  and  the  little  finger,  and  the  greater  part  of  the  metacarpals 
disappeared  by  suppuration.  At  the  present  time  the  patient  is  well,  and  has  the 
bones  of  all  the  fingers  between  the  thumb  and  little  firmer."  This  case  is  of 


Anterior  inlerosseous 

Radial  artery 

Anterior  radial  carpal 


Svperficial  rolar 
Posterior  radial  carpal 
Radial  artery  at  wrist 


Dorsalis  potUcis 

MKtacar/nil  or 

first  dorsal 

inlerosseous 

Princepspollicis 

Dorsalis  indicts 
Jladialis  indicis 


First  dorsal  branch  of  collateral 
digital 


Second  dorsal  branch  of  collateral 
digital 


Anastomosis  of  collateral  digital 
arteries  about  matrix  of  nail 
and  pulp  of  finger 


Ulnar  artery 

Anterior  ulnar 
carpal 

Posterior  ulnar 
carpal 


Deep  ulnar 
Superficial  arch 

Carpal  recurrent 

Posterior  communi- 
cating or  perforat- 
ing 

Palmar  interosseous 

Second,  third,  and 
fourth  palmar 
digital 

Second  and  third 
dorsal  interosseous 

First  palmar  digital 


Anterior  communi- 
cating or  perforat- 
ing 


FIG.   113. — ANASTOMOSES  AND  DISTRIBUTION  OF  THE  ARTERIES  OF  THE  HAND. 


interest  because  the  pathological  process  followed  to  the  letter  the  anatomical 
rule. 

The  vincula  will  be  seen  between  the  flexor  tendons.  They  are  delicate,  sil- 
very, tendinous  threads.  They  aid  the  capillaries  in  passing  from -one  tendon  to 
another.  They  are,  then,  mechanical  devices  for  the  support  of  the  capillaries 
that  nourish  the  synovial  membrane.  In  some  cases  the  vessels  which  they 
support  are  injected,  and  can  be  seen  by  the  unaided  eye. 

The  palmaris  brevis  muscle  (Fig.  110)  arises  from  the  annular  ligament 


1 62  PRACTICAL   ANATOMY. 

and  palmar  fascia,  and  is  inserted  into  the  skin  of  the  hypothenar  eminence.      It 
is  a  corrugator  of  the  integument. 

The  anterior  annular  ligament  (Fig.  1 1 1)  has  passing  under  it  the  follow- 
ing structures  : 

1.  The  median  nerve  and  its  nutrient  artery — arteria  comes  nervi  mediani. 

2.  The  flexor  sublimis  digit  or  nm — musculus  perforatus. 

3.  The  flexor  prof undus  digitorum — musculus  perforans. 

4.  The  flexor  longus  po llicis — between  the  heads  of  the  flexor  brevis. 

To  the  inner  side  of  the  anterior  annular  ligament,  and  intimately  related 
thereto,  you  will  find  the  flexor  carpi  ulnaris  ;  to  the  outer  side,  the  flexor 
carpi  radialis.  Inserted  into  the  anterior  annular  ligament,  and  passing  in 
front  of  the  same,  is  the  palmaris  longus  muscle.  (Fig.  1 10.)  To  the  ulnar 
side  is  the  ulnar,  and  to  the  radial  side  is  the  radial,  artery.  (Fig.  117.) 
This  anterior  annular  ligament  is  a  specialized  part  of  the  deep  fascia.  It  is 
attached  internally  to  the  pisiform  bone  and  unciform  process  of  the  unciform 
bone;  externally,  to  the  scaphoid  tuberosity  and  os  trapezium.  (Fig.  109.) 
Cut  through  the  annular  ligament ;  pull  the  sides  forcibly  apart  as  far  as  pos- 
sible. There  are  two  portions  of  the  palmar  bursa  :  (i)  The  radial,  correspond- 
ing to  the  flexor  longus  hallucis  ;  (2)  the  ulnar,  corresponding  to  the  flexor 
sublimis  digitorum  and  flexor  profundus  digitorum.  (Fig.  107.) 

To  Dissect  the  Median  Nerve  in  the  Hand  (Fig.  1 1 1). — You  will  now  see  the 
median  nerve,  as  large  as  a  lead-pencil,  lying  on  the  flexor  sublimis  digitorum. 
This  nerve  is  involved  in  the  synovial  membrane,  and  it  will  require  the  aid  of 
the  forceps  to  liberate  the  same.  Place  your  left  index  finger  under  the  nerve, 
carefully  lifting  the  same  upward  ;  now  begin  to  trace  out  the  following  branches 
(Fig.  in)  :  (i)  To  the  thumb  ;  (2)  to  the  index  finger,  the  middle  finger,  and 
radial  side  of  the  ring  finger ;  (3)  a  communicating  branch  to  thje  ulnar  nerve. 
You  will  see  these  branches  given  off  from  an  enlargement.  Trace  the  branches 
downward  and  observe  them  passing  behind  the  superficial  palmar  arch.  (Figs. 
1 1 1  and  1 13.) 

The  branches  of  the  median  nerve,  after  passing  behind  the  superficial  palmar 
arch,  accompany  arterial  branches  of  the  superficial  and  deep  palmar  arches  to 
the  fingers.  (Fig.  in.)  These  arteries  and  nerves  are  called  digital  branches. 
Note  that  at  the  superficial  palmar  arch  the  nerves  lie  behind,  but  in  the  fingers 
the  nerves  lie  in  front  of,  the  arteries.  Trace  these  digital  arteries  and  nerves 
to  the  ends  of  the  finger,  and  see  the  distal  digital  anastomotic  arterial  arch. 
(Fig.  1 13.) 

The  Ulnar  Nerve  in  the  Hand. — Find  the  ulnar  nerve  crossing  the  annular 
ligament  (not  under  it).  It  lies  to  the  ulnar  side  of  the  ulnar  artery,  and  some- 
what deeper.  Trace  it  down  and  find  it  dividing  into  two  branches  :  (i)  The 
superficial  palmar  ;  (2)  the  deep  palmar.  The  former  gives  off  branches  to  the 
skin,  to  the  palmaris  brevis  muscle,  and  digital  branches  which  accompany 
arteries  to  the  little  finger  and  one-half  of  the  ring  finger.  Trace  these  branches 
to  the  finger  end  and  observe  the  distal  digital  anastomotic  nerve  loop.  ( Fig. 
ill.)  The  deep  palmar  branch  of  the  ulnar  nerve  accompanies  the  deep  arch, 
and  will  be  described  in  its  proper  place  on  page  164. 

The  musculi  lumbricales  (Fig.  112)  are  four  in  number.  Cut  the  tendons 
of  the  flexor  sublimis  as  shown  in  figure  112.  These  muscles  arise  from  the 
tendons  of  the  flexor  profundus  digitorum  muscle.  Trace  them  on  the  thumb 
side,  to  the  extensor  communis  digitorum,  where  they  are  inserted.  The  ulnar 
two  interossei  muscles  are  supplied  by  the  ulnar,  the  radial  two  by  the  median, 
nerve. 

The  thenar  muscles,  or  muscles  of  the  thumb  (Figs.  109  and  114): 

i.   The  abductor  pollicis,  abducts  first  phalanx. 


SHOULDER,   ARM,   FOREARM,  AND  HAND. 


163 


2.  The  flexor  brevis  pollicis,  flexes  first  phalanx. 

3.  The  opponens  pollicis,  acts  on  metacarpal. 

4.  The  adductor  pollicis,  adducts  the  first  phalanx. 

The  abductor  pollicis  (Fig.  iio)is  easily  isolated.  Cut  the  same  near  its 
insertion,  and  turn  it  aside  so  as  to  preserve  the  nerve-supply.  (Figs.  109  and 
114.)  This  muscle  arises  from  the  bone  at  the  base  of  the  thumb — the  os 
trapezium — and  the  annular  ligament.  It  is  inserted  into  the  base  of  the  thumb, 
proximal  phalanx.  (Fig.  109.) 

The  opponens  pollicis  is  inserted  into  the  whole  length  of  the  thumb  meta- 
carpal bone.  (Fig.  109.)  It  arises  from  the  os  trapezium  and  annular  ligament. 
(Fig.  114.) 


Flexor  carpi 
ulnaris 


Pronator  quadratus 


Abductor  pollieis 


Outer  head  of  flexor 
brevis  pollicis 


Inner  head  of  flexor 

breyis  pollieis  (first 

division) 

Opponens  pollicis 
Inner  head  of  flexor 

breyis  pollicis  (third 

division) 

Inner  head  of  flexor 
breyie  pollicis  (second 
division) 

Adductor  pollicis 


Dorsal  interoaseous 


Third  palmar 
interosseoua 


Fourth  dorsal 
mterosseous 
Second  palmar  iuterosseous 


First  palmar  interoaseous 
Third  dorsal  intsrosseous 

Second  dorsal  interoaseous 

FIG.  114. — THE  PRONATOR  QUADRATUS  AND  DEEP  VIEW  OF  THE  PALM. 


Tlie  flexor  brevis  pollicis  has  two  heads,  and  between  these  two  heads  lies  the 
tendon  of  the  flexor  longus  pollicis  muscle.  The  outer,  or  more  superficial  head 
(Fig.  114),  arises  from  the  os  trapezium  and  annular  ligament,  and  is  inserted 
into  the  base  of  the  first  thumb  phalanx  on  the  outer  side.  (Fig.  109.)  The 
deep  or  inner  head  has  two  parts  :  (i)  A  small  part  that  arises  from  the  first 
metacarpal  bone  ;  (2)  a  large  part  that  arises  from  the  annular  ligament,  the  os 
magnum,  and  the  second  and  third  metacarpals.  (Fig.  1 14.) 

This  latter  is  described  by  some  authors  as  the  oblique  part  of  the  adductor 
pollicis.  The  deep  part  of  the  flexor  brevis  is  inserted  into  the  base  of  the  first 
thumb  phalanx  on  the  inner  side. 


164 


PRACTICAL  ANATOMY. 


The  adductor  pollicis  is  the  remaining  muscle.  It  arises  from  the  mctacarpal 
bone  of  the  middle  finger,  the  lower  two-thirds.  It  is  inserted  into  the  base  of 
the  first  thumb  phalanx  on  the  inner  side.  (Fig.  1 14.) 

Nerve-supply. — The  median  nerve  supplies  the  abductor  pollicis,  the  opponens, 
and  the  outer  head  of  the  flexor  brevis  pollicis.  The  ulnar  nerve,  by  its  deep 
palmar  branch,  will  supply  all  the  remaining  muscles  of  the  hand,  all  the  inter- 
ossei  muscles,  the  two  ulnar  lumbricals,  the  little  finger  group  of  small  muscles, 
the  adductor  pollicis,  and  the  inner  head  of  the  flexor  brevis  pollicis.  Now 
trace  out  and  review  the  branches  of  the  median  nerve  to  the  thumb. 

The  hypothenar  muscles,  or  muscles  of  the  little  finger  (Fig.  114): 

1.  The  abductor  minimi  digiti  abducts  the  little  finger. 

2.  The  flexor  brevis  minimi  digiti  bends  the  first  phalanx. 

3.  The  opponens  minimi  digiti  bends  the  metacarpal. 


FIG.  115. — THE  PALMAR  INTEROSSEI. 


The  abductor  minimi  digiti  arises  from  the  pisiform  bone.     (Fig.  109.) 
inserted  into  the  base  of  the  first  phalanx  of  the  little  finger.     (Fig.  109.) 
and  turn  aside,  and  expose  the  two  remaining  muscles — the  flexor  brevis  minimi 
digiti  and  the  opponens  minimi  digiti. 

Note,  as  you  turn  this  muscle  aside,  the  abductor  minimi  digiti — the  d 
palmar  nerve — going  to  join  the  deep  palmar  arterial  arch  from  the  radial  arte 
(Fig.  1 1 6),  whose  course  it  will  now  follow. 

The  flexor  brci'is  minimi  digiti  arises  from  the  unciform  process  of  the  unci- 
form  bone  and  annular  ligament.     It  is  inserted  into  the  base  of  the  first  phalan 
of  the  little  finger.     (Fig.  109.) 

The  opponens  minimi  digiti  arises  from  the  unciform  process  of  the  uncifor 
bone  and  annular  ligament.      It  is  inserted   into  the  whole   length  of  the  met 
carpal  bone  of  the  little  finger.     Trace  branches  from  the  deep  palmar  branch 
the  ulnar  nerve  to  this  group  of  muscles.     (Fig.  1 1 1.) 


SHOULDER,  ARM,  FOREARM,   AND  HAND. 


165 


The  Palmar  Interossei  Muscles  (Figs.  114  and  115).— These  are  three  in 
number.  They  are  physiological  adductors.  They  arise  from  one  side  of  the 
metacarpal  bone  corresponding  to  the  finger,  into  the  base  of  whose  proximal 
phalanx  they  are  inserted.  They  are  inserted  into  the  bases  of  the  proximal 
phalanges  of  the  index,  little,  and  ring  fingers  in  such  a  way  as  to  adduct  these 
fingers  to  the  middle  finger.  Trace  branches  to  them  from  the  deep  palmar 
branch  of  the  ulnar  nerve. 

The  Deep  Palmar  Branch  of  the  Ulnar  Nerve. — You  have  seen  the  ulnar 


Anterior  inter  osseous 

Radial  artery 

Anterior  radial  carpal 


Superficial  volar 

Posterior  radial  carval 
Radial  artery  at  wrist 


Dorsalis  pollicia 

Metacarpal  or 

first  dorsal 

iiiterosseorts 

Pi-inceps  pollici-s 

Dorsalis  indicis 
Radialis  indicis 


Ulnar  artery 

Anterior  ulnar 
carpal 

Posterior  ulnar 
carpal 


Deep  ulnar 
Superficial  arch 

Carpal  recurrent 

Posterior  communi- 
cating or  perforat- 
ing 

Palmar  inlerosseous 


Second,  third,  and 
fourth  palmar 
digital 

Second  and  third 
dorsal  interosseous 

First  palmar  digital 


A  nterior  communi- 
cating or  perforat- 
ing 


First  dorsal  branch  of  collateral 
digital 


Second  dorsal  branch  of  collateral 
digital 


Anastomosis  of  collateral  digital 
arteries  about  matrix  of  nail 
and  pulp  of  finger 

FIG.  116. — ANASTOMOSES  AND  DISTRIBUTION  OF  THE  ARTERIES  OF  THE  HAND. 

nerve  crossing  the  anterior  annular  ligament,  and  dividing,  below  the  pisiform 
bone,  into  superficial  and  deep  palmar  branches.  (Fig.  in.)  You  traced  the 
superficial  branches  to  the  palmaris  brevis,  the  skin  over  the  hypothenar  emi- 
nence, and  to  the  little  finger  and  half  the  ring  finger.  (Fig.  1 1 1.)  You  will  now 
trace  in  review  the  deep  palmar  branch,  between  the  abductor  minimi  digiti  and 
flexor  brevis  minimi  digiti,  and  see  it  join  company  with  the  deep  palmar  arterial 
arch,  and  send  off  branches  to  these  muscles  : 


1 66  PRACTICAL  ANATOMY. 

1.  The  abductor  minimi  digiti  muscle. 

2.  The  flexor  brevis  minimi  digiti  muscle. 

3.  The  opponens  minimi  digiti  muscle. 

4.  The  two  ulnar  lumbricales  muscles. 

5.  The  four  dorsal  interossei  muscles. 

6.  The  three  palmar  interossei  muscles. 

7.  The  adductor  pollicis  muscle. 

8.  The  inner  head  of  the  flexor  brevis  pollicis. 

THE  RADIAL  AND  ULNAR  ARTERIES  IN  THE  HAND  (Fig.  1 16). — It  now  remains 
to  reduce  to  its  simplest  terms  the  blood-supply  of  the  whole  hand. 

The  ulnar  artery  crosses  the  anterior  annular  ligament.  Below  the  pisiform 
bone  it  divides  into  (i)  the  superficial  arch  and  (2)  the  deep  ulnar  branch.  The 
superficial  arch  crosses  the  palm,  resting  on  the  flexor  tendons  under  cover  of  the 
palmar  fascia,  and  terminating  by  anastomosis  in  the  superficial  volar  branch  ot 
the  radial  artery.  From  the  arch  are  given  off  the  first,  second,  third,  and  fourth 
palmar  digital  branches  that  supply  the  second,  third,  fourth,  and  fifth  fingers 
with  blood.  (Fig.  116.) 

The  radial  artery  passes  to  the  back  of  the  hand,  under  the  three  extensor 
muscles  of  the  thumb  ;  passes  between  the  two  heads  of  the  first  dorsal  interos- 
seous  muscle  ;  crosses  the  palm  beneath  the  flexor  tendons,  and  terminates,  by 
anastomosis,  in  the  deep  ulnar  artery.  From  this  arch  are  given  off  five  palmar 
interosseous  arteries.  Three  of  these — the  three  inner — go  to  the  clefts  of  the 
fingers,  where  they  unite  with  the  palmar  digital  brandies  from  the  superficial 
palmar  arch.  The  two  outermost  branches  go  to  the  thumb  and  index  finger 
under  the  special  names  of  prince ps  pollicis  and  radialis  indicis.  (Fig.  1 16.) 

Carpal  arteries  are  four  in  number:  two  from  the  radial  artery — the  anterior 
and  posterior  radial  carpal  ;  two  from  the  ulnar — the  anterior  and  posterior  ulnar 
carpal. 

The  anterior  and  posterior  perforating  arteries  communicate,  through  the 
hand,  with  the  dorsal  interosseous  arteries.  These  are  arteries  from  an  arch 
formed  on  the  back  of  the  carpus  by  anastomosis  between  the  radial  and  ulnar 
posterior  carpals. 


Where  would  yon  look  for  tJic  cephalic  vein  in  the  vicinity  of  the  shoulder? 

Between  the  deltoid  and  pectoralis  major  muscles  ;  the  vein  is  in  a  groo\ 
with  a  small  artery — the  descending  branch  of  the  acromio-thoracic  arter 
(Fig.  105.) 

How  and  where  do  the  superficial,  radial,  median,  and  nlnar  veins  terminati 

They  terminate  opposite  the  elbow  by  changing  their  names. 

The  radial  above  the  elbow  is  called  the  cephalic  vein. 

The  ulnar  above  the  elbow  is  called  the  basilic  vein. 

The  median  breaks  up  near  the  elbow  into  the  median  basilic  and  cephalic. 

What  are  the  vend'  coinites  / 

The  two  companion  veins  attending  deep  arteries  in  the  extremities  of 
body,  below  the  knee  and  below  the  elbow. 

Hcnv  do  the  superficial  veins  communicate  with  the  vctne  comites  / 

By  perforations  in  the  deep  fascia.      H\   these  communicating  veins  the  circ 
ation  internal  to  or  below  the  deep  fascia  is  equali/ed  to  the  circulation  cxtci 
to  the  deep  fascia. 

If  yon  were  going  to  draw  blood  from  a  patient's  arm,  wliy  would  yon  select  the 
median  cephalic  vein  in  preference  to  the  median  basilic  vein  for  venesection  / 


SHOULDER,  ARM,  FOREARM,  AND  HAND.  167 

The  median  basilic  vein  lies  on  the  brachial  artery,  which  latter  would  be 
endangered  were  this  vein  selected. 

Suppose  you  employ  the  median  basilic  vein  in  venesection,  and  accidentally  cut 
the  brachial  artery,  and  your  patient  dies  from  hemorrhage:  In  this  case  w mat 
ground  for  action  for  damages  would  relatives  of  deceased  liavc  that  you  could  not 
possibly  circumvent  ? 

The  ground  of  want  of  ordinary  care.  The  cephalic  vein  would  have 
answered  the  venesection  purpose,  and  its  employment  would  not  have  endan- 
gered your  patient's  life.  Under  the  law,  a  physician  must  possess  ordinary  skill 
and  exercise  ordinary  care. 

Can  you  say  anything  regarding  any  cutaneous  nerves  liable  to  be  injured  in 
phlebotomy  of  the  median  cephalic  and  median  basilic  veins  f 

The  internal  cutaneous  nerve  crosses  the  median  basilic  vein  ;  the  musculo- 
cutaneous  nerve  terminal  crosses  the  median  cephalic — either  may  be  injured. 

Name  the  great  nerve-trunks  that  supply  the  skin  of  the  hand  with  sensation. 

The  median  gives  palmar  and  digital  branches  to  3.5  fingers,  radial  side. 

The  ulnar  gives  palmar  and  digital  branches  to  1.5   fingers,  front  and  back. 

The  musculo-spiral,  radial  nerve,  supplies  3.5  fingers  dorsally. 

Have  the  median,  ulnar,  and  musculo-spiral  nerves  any  articular  distribution  in 
the  joints  of  the  hand  ? 

Yes  ;  they  supply  joints  between  the  phalanges — the  metacarpo-phalangeal, 
the  carpo-metacarpal,  the  intermetacarpal,  the  medio-carpal,  and  the  radio-carpal. 

Is  there  any  systematic  distribution  of  articular  nen>es  f 

Yes  ;  a  nerve-trunk  that  supplies  a  muscle  that  moves  a  joint  supplies  the 
joint  as  well.  The  inferior  radio-ulnar  joint  is  pronated  by  the  pronator  quad- 
ratus,  and  supinated  by  the  supinator  longus.  To  determine  the  nerve-supply  to 
this  joint,  you  ascertain  the  nerve-supply  to  the  muscles  that  move  the  joint.  In 
this  particular  case  the  median  and  musculo-spiral  nerve-trunks  supply  the 
pronator  quadratus  and  supinator  longus  muscles  respectively  ;  these  same  nerves 
supply  the  joint. 

Give  attachments  of  the  anterior  annular  ligament  and  tell  ivhat  structures  pass 
under  the  same. 

This  ligament  is  a  specialized  part  of  the  deep  fascia.  It  is  attached  exter- 
nally to  the  scaphoid  bone  and  os  trapezium  ;  internally  to  the  pisiform  bone  and 
the  unciform  process  of  the  unciform  bone.  Under  this  ligament  pass  the 
median  nerve,  with  its  median  artery,  the  flexor  longus  pollicis,  the  flexor  prp- 
fundus  digitorum,  and  the  flexor  sublimis  digitorum. 

Name,  locate,  and  give  importance  of  three  surgical  areas  of  the  fingers. 

(i)  The  central,  in  which  are  found  the  tendons  of  the  flexors  in  their  synovial 
sheath,  called  theca.  (2)  On  each  side  of  this  tendinous  area  is  a  neuro- vasal  area, 
in  which  are  found  the  digital  arteries  and  nerves  that  supply  the  fingers  with 
blood  and  sensation  respectively. 

Why  is  infection  of  the  little  finger  or  thumb  more  dangerous  than  infection  of 
the  fingers  between  these  two  extremes. 

The  vaginal  thecal  sheaths  of  synovial  membrane  of  these  extremes  are  in 
communication  with  the  great  palmar  bursae  under  the  anterior  annular  ligament. 
Give  the  symptoms  in  paralysis  of  the  ulnar  nerve. 

There  would  be  loss  of  sensation  and  motion  in  those  parts  to  which  this 
nerve  is  distributed,  as  follows  :  (i)  Loss  of  sensation  in  the  skin  of  the  little 
finger  and  the  ulnar  half  of  the  ring  finger  and  in  the  corresponding  articulations  ; 
(2)  loss  of  motion  in  the  flexor  carpi  ulnaris  and  in  half  of  the  flexor  profundus 
digitorum  muscles  ;  (3)  loss  of  motion  in  all  the  interossei  muscles  and  in  the 
two  lumbricals  on  the  ulnar  side  of  the  hand  ;  (4)  loss  of  motion  in  the  flexor  brevis 
minimi  digiti,  in  the  abductor  minimi  digiti,  and  in  the  opponens  minimi  digiti  ; 


1 68  PRACTICAL  ANATOMY. 

(5)  loss  of  motion  in  the  adductor  pollicis  and  in  the  ulnar  head  of  the  flexor 
brevis  pollicis  ;  (6)  loss  of  sensation  in  all  the  intermetacarpal  joints. 

Give  symptoms  in  paralysis  of  the  median  nerve. 

(i)  Loss  of  sensation  in  the  thumb,  index,  middle,  and  half  the  ring  finger, 
on  the  palmar  surface,  and  about  the  roots  of  the  nails  of  the  dorsal  surface  ; 
(2)  loss  of  motion  in  all  the  muscles  of  the  anterior  part  of  the  forearm,  except 
the  muscle  and  a  half  supplied  by  the  ulnar  nerve,  as  previously  explained  ;  (3) 
loss  of  motion  in  the  two  lumbrical  muscles  on  the  radial  side  of  the  hand,  and 
loss  of  motion  in  the  outer  head  of  the  flexor  brevis  pollicis,  in  the  opponens 
pollicis,  in  the  abductor  pollicis. 

Describe  the  blood-supply  of  the  hand. 

The  ulnar  and  radial  arteries  terminate  in  the  superficial  and  deep  palmar 
arches  respectively.  These  arches  give  off  branches  to  the  hand  and  fingers. 
(Fig.  1 1 6.) 

Describe  the  superficial  palmar  arch. 

This  arch  is  a  continuation  of  the  ulnar  artery  across  the  hand.  It  anasto- 
moses with  the  superficialis  volae — a  branch  of  the  radial  artery — to  complete  the 
arch.  The  arch  may  be  completed  by  anastomosis  with  the  radialis  indicis  or 
princeps  pollicis,  both  branches  of  the  radial  artery  also.  The  superficial  arch 
gives  off  four  branches — called  first,  second,  third,  and  fourth  palmar  digital 
branches — when  enumerated  toward  the  thumb.  The  first  palmar  digital  artery 
supplies  the  ulnar  side  of  the  little  finger  ;  each  of  the  three  others  divides  into  two 
collateral  digital  branches.  The  radial  side  of  the  index  finger  is  supplied  by  the 
radialis  indicis  ;  the  thumb  by  the  princeps  pollicis.  The  digital  branches  from 
the  superficial  arch  are  joined,  opposite  the  clefts  of  the  fingers,  by  (i)  the  palmar 
interosseous,  branches  of  the  deep  palmar  arch  ;  (2)  by  the  inferior  perforating 
arteries  from  the  dorsum  of  the  hand. 

Describe  the  deep  palmar  arch. 

This  arch  is  a  continuation  of  the  radial  artery  across  the  hand.  It  anasto- 
moses with  the  deep  branch  of  the  ulnar  artery.  (Fig.  116.)  It  begins  at  the 
first  interosseous  space,  and  rests  on  the  metacarpal  bones  close  to  their  carpal 
ends.  The  arch  is  attended  by  the  deep  branch  of  the  ulnar  nerve  as  described 
on  page  164.  The  deep  arch  gives  off  three  palmar  interosseous  arteries,  which 
inosculate  with  the  digital  branches  of  the  superficial  arch  at  the  clefts  of  the 
fingers.  All  the  digital  branches  are  attended  by  collateral  nerve  branches  of  the 
median  and  ulnar  nerves. 


THE  FOREARM. 

In  this  region  you  must  review  the  osteology  of  the  radius  and  ulna,  and 
become  familiar  with  eminences,  depressions,  that  are  associated  with  the  origin, 
insertion,  and  location  of  muscles.  You  must  be  able  to  name  all  the  articular 
surfaces,  and  give  the  rule  of  occupancy  for  their  n«mes.  You  must  name  tech- 
nically all  articulations,  and  give  the  rule  for  writing  compound  words. 

The  Radius  (Fig.  124). 

Name  tlic  important  points  on  t/iis  bone  concerned  in  practical  anatomy. 

The  radial  head  and  its  concave  and  convex  articular  surfaces. 

The  bicipital  tuberosity  for  the  tendon  of  the  biceps  and  for  a  bursa. 

The  ulnar  articular  surface  for  the  lesser  sigmoid  cavity  of  the  ulna. 

The  humeral  articular  surface  for  articulation  with  the  capitellum. 


SHOULDER,  ARM,  FOREARM,  AND   HAND.  169 

The  neck  of  the  radius  located  above  the  bicipital  tuberosity. 

The  oblique  line  of  the  radius — a  very  important  structure. 

The  styloid  process,  with  base  and  apex  for  ligament  and  muscle. 

The  sigmoid  cavity,  for  articulation  with  the  head  of  the  ulna. 

The  semilunar  and  scaphoid  articular  surfaces. 

The  nutrient  foramen,  directed  upward  according  to  rule. 

The  interosseous  border,  for  the  interosseous  membrane. 

The  anterior  surface,  occupied  by  deep  flexor  muscles. 

The  posterior  surface,  occupied  by  deep  extensor  muscles. 

The  outer  surface,  occupied  by  muscles. 

Describe  tlie  anterior  surface  of  the  radius. 

The  oblique  line  of  the  radius  extends  from  the  bicipital  tuberosity  to  the 
insertion  of  the  pronator  radii  teres  on  the  outer  border  of  the  bone.  (Fig.  124.) 
This  line  may  be  viewed  as  consisting  of  three  lips  :  (i)  An  upper  one,  into  which 
the  supinator  brevis  is  inserted  ;  (2)  a  middle  one,  from  which  the  radial  head 
of  the  flexor  sublimis  digitorum  muscle  takes  its  origin  ;  (3)  an  inferior  one,  from 
which  the  flexor  longus  pollicis  takes  its  origin.  This  surface  gives  origin 
below  the  oblique  line  to  the  flexor  longus  pollicis  and  insertion  to  the  pronator 
quadratus. 

Wliat  can  you  say  of  the  external  surface  of  tJie  radius  ? 

Its  upper  one-half  is  occupied  by  the  supinator  brevis  and  pronator  radii  teres  ; 
its  lower  one-half  is  overlapped  by  the  radial  extensors  of  the  carpus,  and  crossed 
by  the  extensor  ossis  metacarpi  pollicis  and  extensor  brevis  pollicis  ;  this  latter 
muscle  is  also  called  extensor  primi  internodii  pollicis. 

What  can  you  say  of  the  posterior  surface  of  the  radius  f 

Its  upper  one-third  gives  origin  to  the  radial  part  of  the  extensor  ossis  meta- 
carpi pollicis  and  the  extensor  primi  internodii  pollicis  ;  the  part  of  the  bone 
below  this  is  covered  by  the  tendons  of  the  two  preceding  muscles. 

The  Ulna.     (Fig.  124.) 

Name  the  important  bony  parts  of  the  ulna  and  give  their  importance  in  prac- 
tical anatomy. 

The  olecranon  process,  for  the  insertion  of  the  triceps  muscle. 

The  coronoid  process,  for  the  insertion  of  brachialis  anticus  muscle. 

The  greater  sigmoid  fossa,  for  articulation  with  the  humerus. 

The  lesser  sigmoid  fossa,  for  articulation  with  the  radius. 

The  oblique  line,  for  attachment  of  the  supinator  brevis  muscle. 

The  interosseous  ridge,  for  attachment  of  the  interosseous  membrane. 

The  styloid  process  (apex),  for  internal  lateral  ligament  of  wrist. 

The  head  articulates  with  the  ulnar  sigmoid  cavity  of  the  radius. 

The  base  of  the  styloid  process,  for  the  insertion  of  the  supinator  longus. 

The  anterior  surface  of  the  ulna  is  for  muscular  origin. 

The  inner  surface  of  the  ulna  is  for  muscular  origin. 

The  posterior  surface  of  the  ulna  is  for  muscular  origin. 

Explain  the  anterior  surface  of  the  ulna. 

It  has  the  nutrient  foramen,  which,  according  to  the  rule,  is  directed  toward 
the  elbow.  It  gives  origin  to  the  flexor  profundus  digitorum  and  pronator 
quadratus  muscles.  This  surface  is  limited  by  the  anterior  border,  the  interos- 
seous border,  and  an  oblique  line. 

What  can  you  say  of  the  internal  surface  of  the  ulna  ? 

It  is  occupied  by  the  flexor  profundus  digitorum  in  its  upper  three-fourths  ; 
the  remainder  of  this  surface  of  the  ulna  is  subcutaneous. 

What  can  be  said  of  the  posterior  surface  of  the  ulna  ? 

This  is  the  most  difficult  part  of  the  bone,  but  must  be  mastered  before  you 
can  appreciate  the  attachment  of  certain  muscles.  This  surface  is  subdivided  by 


170  PRACTICAL   ANATOMY. 

two  lines,  an  oblique  and  a  vertical  one,  into  three  smaller  surfaces.  Above  the 
oblique  line,  which  runs  from  the  lesser  sigmoid  cavity  to  the  posterior  border  of 
the  bone,  is  the  anconeus  muscle.  To  the  oblique  line  the  supinator  brevis 
muscle  is  attached.  The  surface  below  the  oblique  line  is  divided  by  a  vertical 
line  into  an  internal  and  an  external  portion. 

What  can  you  say  of  the  portion  of  the  posterior  surface  of  the  ulna  internal 
to  the  vertical  line  ? 

It  gives  origin  to  the  extensor  carpi  ulnaris  muscle. 

What  can  you  say  of  the  portion  of  the  posterior  surface  of  the  ulna  external 
to  the  vertical  line  ? 

It  gives  attachment  to  the  supinator  brevis,  the  extensor  ossis  metacarpi  pol- 
licis,  the  extensor  longus  pollicis,  and  the  extensor  indicis  muscles. 

Does  t/ie  head  of  the  ulna  enter  into  the  formation  of  the  wrist-joint  f 

No ;  the  triangular  fibro-cartilage  intervenes.  The  head  of  the  ulna  articu- 
lates with  the  sigmoid  fossa  in  the  lower  end  of  the  radius,  forming  the  inferior 
radio-ulnar  articulation. 

The  Humerus.     (Fig.  129.) 

Locate,  classify,  and  describe  geometrically  the  humerus. 

It  is  the  arm  bone,  located  between  the  shoulder  and  elbow,  and  long  by  clas- 
sification. It  has  an  outer,  an  inner,  and  a  posterior  surface.  It  has  an  anterior, 
an  external,  and  an  internal  border.  It  has  a  superior  extremity  or  upper  one- 
third  ;  an  inferior  extremity  or  lower  one-third  ;  a  middle  one-third. 

Name  the  bony  parts  of  the  Jnimerus  concerned  in  practical  anatomy,  and  give 
their  practical  importance. 

The  head  of  the  humerus  articulates  with  the  head  of  the  scapula. 

The  anatomical  neck  gives  attachment  to  the  capsule. 

The  surgical  neck  is  very  often  the  seat  of  fracture. 

The  bicipital  groove  lodges  the  long  head  of  biceps  muscle. 

The  bicipital  lips  surmount  and  deepen  the  bicipital  groove. 

The  greater  tuberosity  gives  tendinous  insertion  to  three  muscles. 

The  lesser  tuberosity  gives  tendinous  insertion  to  one  muscle. 

The  internal  condyle  is  developed  by  traction  of  flexors  and  pronators. 

The  internal  condylar  ridge  has  the  internal  intermuscular  septum. 

The  external  condyle  is  developed  by  extensors  and  supinators. 

The  external  condylar  ridge  has  the  external  intermuscular  septum. 

The  capitellum  articulates  with  the  concave  surface  of  the  radius. 

The  trochlea  articulates  with  the  greater  sigmoid  of  the  ulna. 

The  coronoid  fossa  is  produced  mechanically  by  the  coronoid  process. 

The  olecranon  fossa  is  produced  mechanically  by  the  olecranon  process. 

The  radial  depression  is  produced  by  the  head  of  the  radius. 

Name  the  muscles  inserted  into  the  greater  tuberosity  of  the  liumerus. 

The  supraspinatus  into  the  upper  facet ;  the  infraspinatus  into  the  middle 
facet ;  the  teres  minor  into  the  lower  facet. 

HOT.V  is  the  lesser  tuberosity  occupied  f 

By  the  tendinous  insertion  of  the  subscapularis  muscle.     It  has  one  facet  only. 

Where  is  the  transverse  hum era/  ligament  and  what  is  its  function  f 

It  extends  from  the  greater  to  the  lesser  tuberosity  of  the  humerus,  convert- 
ing the  bicipital  groove  into  a  canal  for  the  lodgment  of  the  long  or  scapular  head 
of  the  biceps  muscle. 

Hoiv  would  you  locate  the  surgical  neck  of  the  humerus  f 

It  is  the  constricted  portion  of  the  bone  below  the  tuberosities.  It  is  the 
portion  of  the  humerus  most  frequently  fractured  in  the  upper  one-third. 

H&iv  do  the  three  fossa  of  the  liumerus,  in  the  vicinity  of  the  elbow  enhance  the 
gravity  of  a  fracture  passing  through  them  f 


SHOULDER,  ARM,  FOREARM,  AND  HAND.  171 

They  may  become  filled  with  provisional  callus  and  bone,  when  a  stiff  joint 
will  be  the  result. 

Hoiv  is  the  posterior  surface  of  the  humcrus  occupied  / 

By  the  long  humeral  head  of  the  triceps  above  the  musculo-spiral  groove  ; 
by  the  short  humeral  head  below  the  groove  ;  by  the  musculo-spiral  groove,  in 
which  are  the  musculo-spiral  nerve  and  superior  profunda  artery. 

How  is  the  outer  lip  of  the  bicipital  groove  occupied  ? 

By  the  tendinous  insertion  of  the  pectoralis  major  muscle. 

How  are  the  outer  and  inner  surfaces  of  tlic  Juuneriis  occupied  ? 

They  are  occupied  by   the   pectoralis   major,  deltoid,  and   brachialis  anticu 
on  the  outer  ;  the  teres  major,  latissimus  dorsi,  coraco-brachialis,  and  brachialis 
anticus  on  the  inner  surface. 

How  is  the  external  condylar  ridge  occupied  ? 

By  the  supinator  longus  and  the  extensor  carpi  radialis  longior  ;  the  former 
occupies  the  upper  two-thirds,  the  latter  the  lower  one-third  of  the  ridge. 

Name  all  the  muscles  attached  to  the  middle  one-third  of  the  Jiuinerus  wliose 
action  would  tend  to  displace  the  fragments  in  case  of  fracture  in  this  locality. 

The  long  and  short  humeral  heads  of  the  triceps,  the  deltoid,  the  coraco- 
brachialis,  the  brachialis  anticus  muscles. 

What  might  be  the  most  serious  complication  of 'a  fracture  in  the  middle  one- 
tJiird  of  the  liumerus? 

Compression  and  paralysis  of  the  musculo-spiral  nerve,  in  which  there  would 
be  inability  to  extend  the  carpus  and  digits  and  to  supinate  the  radius. 

What  is  the  direction  taken  by  the  nutrient  foramen  of  the  humcrus  ? 

It  conforms  to  the  rule  governing  the  direction  of  these  foramina  in  the  long 
bones  of  the  extremities  :  to  the  elbow  and  from  the  knee  being  the  rule. 

Hoiv  many  muscles  and  ligaments  are  attached  to  the  humerus  ? 

There  are  twenty-five  muscles  and  eight  ligaments  attached. 

In  this  region  you  will  find  the  following  arrangement  of — 

Muscles  Physiologically  Grouped. 

Carpal  Flexors.  Flexor  carpi  radialis. 

Flexor  carpi  ulnaris. 

Palmaris  longus. 
Digital  Flexors.  Flexor  sublimis  digitorum. 

Flexor  profundus  digitorum. 

Flexor  longus  pollicis. 
Radial  Pronators.        Pronator  radii  teres. 

Pronator  radii  quadratus. 
Forearm  Flexors.         Flexor  biceps  cubiti. 

Flexor  cubiti  brachialis  anticus. 

Flexor  brachio-radialis. 
Nerves.  Median  nerve  and  its  branches. 

Ulnar  nerve  and  its  branches. 

Musculo-cutaneous  nerve  and  its  branches. 
Arteries  and  Veins.      Radial  artery  and  the  deep  palmar  arch. 

Ulnar  artery  and  the  superficial  palmar  arch. 

Common  interosseous  artery  and  vein. 

Anterior  interosseous  artery  and  vein. 

Posterior  interosseous  artery  and  vein. 
Surgical  Areas.  The  cubital  fossa  and  its  contents. 

The  radial  groove  and  its  contents. 

The  ulnar  groove  and  its  contents. 


172  PRACTICAL  ANATOMY. 

The  cubital  fossa  has  geometrically  a — 

1.  Roof,  formed  by  the  skin  and  fasciae — superficial  and  deep. 

2.  Floor,  formed  by  the  brachialis  anticus  and  supinator  brevis. 

3.  Superior  border,  formed  by  an  imaginary  line  from  condyle  to  condyle. 

4.  Outer  border,  formed  by  the  brachio-radialis  muscle. 

5.  Inner  border  farmed  the  pronator  radii  teres  muscle. 


Inferior  profunda  artery 
A  iiastoiiio/icft  magna  artery 


Braehiul  artery 
Radial  recurrent  artery  . 

Supinator  longus 
Radial  artery. 

Flexor  longus  pollicis  muscle 


•Brachialia  anticus  muscle 

Aiili-rior  nhiiir  rri'iirrenl 
'  Posterior  ulnar  recurrent 

-Ulnar  artery 

Anterior  interosseous  artery 
Flexor  carpi  ulnaris 

Flexor  profundus  digitorum  muscle 
Anterior  interosseous  artery 


Anterior  annular  ligament,  out  - 


Anterior  branch  of  ulnar  artery,  cut 
Deep  pal  mar  arch 

Palmar  interosseous  arteries 
Palmar  digital  artery,  oil  short 


Collateral  branch  of  palmar  digital  artery 


J 


FIG.   117. — TIIK  AKTKRIKS  OK  Tin;   FoRKAR] 


ii    MIK  DKKI-  P.M. MAR  ARCH. 


The  fossa  contains  the  following  structures — 

(i)  The  brachial  artery  and  veins  ;  (2)  the  radial  artery  ;  (3)  the  ulnar  artery  ; 
(4)  the  tendon  of  the  biceps  muscle  ;    (5)  the   median   nerve  ;    (6)  the  musculo- 
spiral   nerve  ;  (7)   the    radial  recurrent  artery  ;  (8)  the   ulnar   recurrent  artery 
(9)  the  common  interosseous  artery. 

The  radial  groove  has  these  geometrical  parts  : 


SHOULDER,  ARM,  FOREARM,  AND  HAND.  173 

1.  Roof,  formed  by  skin  and  fasciae — superficial  and  deep. 

2.  Floor,  formed  by  flexor  longus  pollicis  and  pronator  quadratus. 

3.  Outer  border,  formed  by  supinator  longus  or  brachio-radialis  muscle. 

4.  Inner  border,  formed  by  the  flexor  carpi  radialis  and  pronator  radii  teres. 

5.  Contents,  consisting  of  the  radial  artery  and  its  venae  comites. 
The  ulnar  groove  has  these  geometrical  parts  : 

1 .  Roof,  formed  by  the  skin  and  fasciae,  superficial  and  deep. 

2.  Floor,  formed  by  the  flexor  profundus  digitorum  muscle. 


MEDIAN  NERVE 

Posterior  branch  of 

anastomotica  magna 

BRANCHES  OF     ( 

INTERNAL   CUTA-J. 

NEOUS  NERVE     (_ 

Posterior  ulnar  vein 

Brachialis  anticus 

Anterior  branch  of 
anastomotica  magna 
Anterior  ulnar  ruin 

Median  basilic  vein 

MUSCULAR  BRANCH 
OF  MEDIAN  NER  VE 


Tendon  of  biceps 
Bieipital  fascia 


Erachialis  anticus 

Deep  median  vein 

Ulnar  artery 

Pronator  teres 


Radial  artery 


Biceps 

Internal  vena 
comes  of 
brachial  artery 
Basilic  vein 

Brachialis 
anticus 

Cephalic  vein 

Brachial  artery 
EXTERNAL 

CUTANEOUS 

NER  VE 
Musculo-spiral 
n.  and  ascending 
branch  of  radial 
recurrent  artery 
Radial  vein 
Median  cephalic 

vein 

Ascending  br.  of 
radial  recurrent 
RADIAL 

NERVE 
Radial  recurrent 

artery 
Supinator 
'  longus 

Descending  br. 

of  radial 

recurrent 
Median  vein 

RADIAL 
NERVE 


FIG.    118. — THE  BEND  OF  THE  EI.HUW  WITH  THE  SUPERFICIAL  VEINS. 
(From  a  dissection  by  Dr.  Alder  Smith  in  the  Museum  of  St.  Bartholomew's  Hospital.) 


3.  Outer  border,  formed  by  the  flexor  sublimis  digitorum  muscle. 

4.  Inner  border,  formed  by  the  flexor  carpi  ulnaris  muscle. 

5.  Contents,  which  are  :   ulnar  artery,  vena?  comites,  and  ulnar  nerve. 
Dissection  (Fig.  117).     The  Radial  Artery. — Cut  through  the  roof  of  the 

groove.  Then,  with  your  scissors  and  forceps  or  director,  follow  the  artery  up 
to  the  bifurcation  of  tlic  brachial  artery.  Observe  the  numerous  small  muscular 
branches  that  are  given  off  by  this  artery  both  to  muscles  and  skin. 

The  Ulnar  Artery. — Cut  through  the  roof  of  its  groove  and  follow  it  up  as 
far  as  you  can  without  cutting  into  the  flexor  sublimis  digitorum  muscle.      Note 


174 


PRACTICAL  ANATOMY. 


the  presence  of  the  ulnar  nerve  on  its  inner  or  ulnar  side.  Find  also  where  this 
nerve  gives  off  its  dorsal  ulnar  cutaneous  branch,  to  be  distributed  to  the  dorsum 
of  the  little  finger  and  half  of  the  ring  finger. 

The  Cubital  Fossa. — Figure  1 18  shows  the  superficial  dissection  of  this  area 
you  have  already  made.  Now  cut  the  bicipital  fascia  with  scissors,  and  develop 
the  brachial  artery  and  its  branches,  and  make  your  dissection  look  like  figure 
1 19.  Note  (i)  the  brachial  artery  ;  (2)  to  the  inner  side  of  this  artery  the  median 
nerve;  (3)  to  the  outer  side  of  the  artery  the  tendon  of  the  biceps  muscle; 
(4)  to  the  outer  side  of  the  tendon  of  the  biceps,  see  the  musculo-spiral  nerve, 
deeply  located  between  the  brachialis  anticus  muscle  and  the  supinator  longus 
muscle,  dividing  into  the  radial  and  posterior  interosseous  nerves.  Find  also 


POSTERIOR  BRANCH 

OF  INTERNAL 

CUTANEO  US  NER  VE 
ANTERIOR  BRANCH 

OF  INTERNAL 

CUTANEOUS  NERVE 

Brachial  artery 


BRANCH  TO 
PRONATOR  TERES 

Bicipital  fascia,  cut 

Pronator  radii  tercs 
muscle 

MEDIAN  NERVE 

Ulnar  artery 


Biceps  muscle 


BRANCH  OF  MUSCULO- 
SPIRA  L  NER  VE  TO 
SUPINA  TOR  LONG  US 


RADIAL  NERVE 


Radial  recurrent  artery 
,i>,,l  POSTERIOR 
INTEROSSEO  US 
NERVK 

Tendon  of  biceps 

MUSCUL  O-  CUTA  NEO  US 
NERVE 


'• —   Supinator  longus  muscle 


j Radial  artery 


FIG.   119. — THE  BKACHIAI.  ARTERY  AT  TIN    I'.KND  OK  THE  Ku;»\v. 


the  muscular  branches  to  the  pronator  radii  tores  and  supinator  longus  muscles, 
from  the  median  and  musculo-spiral  nerves  respectively. 

Carefully  remove  the  deep  fascia  from  the  muscles  and  your  dissection  of  the 
cubital  fossa  will  look  like  figure  I  20.  You  will  now  find  each  tendon  individual;}-, 
as  in  figure  120,  near  the  annular  ligament;  trace  it  up  to  the  muscular  mass 
from  which  it  comes  ;  then  refer  to  the  figure  for  the  name  of  the  structure. 
Caution  :  As  you  thus  in  cleaning  the  muscles  one  by  one  remove  the  deep  fasc  ia 
from  the  muscles,  do  not  destroy  the  superficial  vessels  and  nerves — divide  only 
the  connective  tissue-. 

For  convenience  of  dissection  develop  the  muscles  of  first  group  (Fig.  120): 
I.    Pronator  radii  tcrcs  :  origin,  inner  comlyle  and  coronoid  process. 


SHOULDER,  ARM,  FOREARM,  AND  HAND.  175 

2.  Paliuaris  longns ;  origin,  inner  condyle  by  the  common  tendon. 

3.  Flexor  carpi  radialis  ;  origin,  inner  condyle  by  the  common  tendon. 

4.  Flexor  carpi  ulnaris;  origin,  inner  condyle  and  olecranon.     The  flexor  carpi 
ulnaris  has  two  heads,  with  the   ulnar  nerve  between  them.      This  muscle  also 


Triceps 


Brachialis  antieus 


Pronator  radii  tares 


Flexor  carpi  radialis 


Palraaris  longus 


Flexor  carpi  ulnaris 


sublimia  digitorum 


Biceps 


Brachio-radialis 


Flexor  longus  pollioia 


FIG.  120.— FRONT  OF  THE  FOREARM:  FIRST  LAYER  OF  MUSCLES. 


forms  one  of  the  boundaries  for  the  ulnar  groove.  Notice  carefully  the  extensive 
insertion  of  the  flexor  carpi  ulnaris  muscle  into  (i)  the  pisiform  bone,  (2)  the 
unciform  bone,  (3)  the  anterior  annular  ligament,  (4)  the  base  of  the  fifth  meta- 
carpal  bone. 


i76 


PRACTICAL  ANATOMY. 


The  flexor  carpi  radialis  muscle  (Fig.  120)  is  seldom  properly  dissected  by 
the  student  to  its  specific  insertion.  Trace  its  tendon  through  two  canals,  and  to 
two  bones  for  insertion  ;  one  canal  is  on  the  outer  side  of  the  annular  ligament, 
the  other  is  in  the  bone  at  the  base  of  the  thumb — the  OS  trapezium.  The 
muscle  is  inserted  into  the  bases  of  the  second  and  third  metacarpals. 


lo 


FIG.   121. — SUPERFICIAL  MUSCLES  OK  PALMAR  Asn-.i  i   »i    FOKKAKM. 

I.  Lower  portion  of  biceps.  2.  Bicipital  fascia.  3.  Tendon  of  insertion  into  radius.  4,  4.  Brachialis 
aniicus.  5.  Internal  head  of  triceps  6.  Pronator  radii  teres.  7.  Flexor  carpi  radialis.  8.  Pal- 
maris  longus.  9.  Its  termination  in  palmar  ligament.  10.  Flexor  carpi  ulnaris.  II.  Its  attachment 
to  pisiform  hone.  12.  Supinator  longus.  13.  Its  attachment  to  styloid  process  of  radius.  14,  14. 
Extensor  carpi  radialis  longior.  15.  Extensor  carpi  radialis  brevior.  16.  Extensor  ossis  metacarpi 
pollicis.  17.  Its  tendon  of  insertion  into  base  of  first  metacarpal  hone.  18.  Tendon  of  extensor 
secuncli  internody  pollicis.  19,  19.  Flexor  suhlimis  dighorum.  20,  2O.  Tendons  of  this  muscle. 
21,  21.  Their  attachment  to  second  phalanges  of  fingers.  22,  22.  Attachment  of  tendons  of  flexor 
profundus  digitorum  to  last  phalanges  of  lingers.  23,  23.  Lumhricales.  24.  Abductor  pollicis. 
25.  Its  insertion  into  fir.^t  phalanx  of  thumb.  26,  26.  Flexor  longus  pollicis.  27.  Flexor  brevis 
minimi  digiti.  28.  Abductor  minimi  digiti. 

The  palmaris  longus  muscle  is  properly  a  tensor  of  the  palmar  fascia.  The 
muscle  is  inserted  into  the  annular  ligament  and  also  into  the  palmar  fascia.  It 
is  often  absent.  It  is  a  decided  flexor  of  the  carpus. 


SHOULDER,  ARM,   FOREARM,  AND   HAND. 


177 


The  pronator  radii  teres  muscle  must  first  be  separated  from  the  flexor  carpi 
radialis,  by  dividing  the  connective  tissue  with  scissors  and  forceps.  Next  pull 
the  brachio-radialis  outward,  and  expose  the  insertion  of  the  pronator  radii  teres 
into  the  middle  third  of  the  outer  surface  of  the  radial  shaft.  Now  trace  the 


Biceps 
Triceps 


Muscles  of  first  layer 
Brachialis  anticus 


Flexor  sublimis  digitorum  L~ 


Flexor  carpi  ulnaris 


Plexor  carpi  radialis 
Falmaris  longus 


Brachio-radialis 


Extensor  carpi  radialis  iongior 

Supinator  brevis 


Brachio-radialia 
Flexor  longus  pollicis 

Extensor  ossis  metacarpi  pollicis 
Extensor  brevis  pollicis 


FIG.   122. — FRONT  OF  THE  FOREARM:  SECOND  LAYER  OF  MUSCLES. 


median  nerve  down,  and  see  it  pass  between  the  two  heads  of  the  pronator  radii 

teres,  to  reach  the  under  surface  of  the  flexor  sublimis  digitorum.      (Fig.  119.) 

The  ulnar  artery's  course  (Fig.  117)  to  reach   its  groove  as  described  on 

page  172  ;    Cut  the  origins  at  the  internal  condyle,  of  the  pronator  radii  teres, 


i78 


PRACTICAL   ANATOMY. 


BRACIHAL  PLEXUS 


HEAD  OF  HUMERUS 
Fectoralis  minor,  turned  back 

MUSCULO-CUTANEOUS  NERVE 
BRANCH   OF  MUSCULO-CUTA- 
NEOUS TO   MEDIAN  NERVE 
Coraco-brachialis 


Brachial  artery 

Superior  profunda  artery 
Biceps 


MUSCULO-CUTANEOUS  NERVE  — 

BRANCH  OF  MUSCULO-CUTA- 
NEOUS NERVE  TO  BRACHI- 
ALIS  ANTICUS 

Brachialis  anticua 
MEDIAN  NERVE 

Inner  brachial  vena  comes 
MUSCULO-SPIRAL  NERVE 

Radial  recurrent  artery 
Supinator  longus 

Superficial  median  vein,  cut  short 


Fronator  radii  teres,  superficial 
head,  cut 


RADIAL  NERVE  . 


Radial  artery 


Cut  edge  of  flexor  sublimis 
digitorum 


MEDIAN  NERVE 


Flexor  lougua  pollioiB 


Subacapularis 
Acromio-thoracic  artery 
Axillary  <nier>/ 
MEDIAN  NERVE 
Subscapular  artery 

Teres  major 
Latissimus  dorsi 

Long  head  of  triceps 
MUSCULO-SPIRAL  NERVE 

)  MUSCULAR  BRANCH  OF 
}-     M I  -SCULO-SPIRA  L 
)      NER  VE 


R  •  i Inferior  profunda  artery 


Inner  head  of  triceps 
ULNAR  NERVE 

Anaslomotica  magna  artery 
Internal  intermuscular  septum 


MUSCULAR  BRANCHES  OF 
MEDIAN  NERVE 

Pronator  teres  and  superficial 
flexor  muscles,  turned  back 

Anterior  ulnar  recurrent  artery 

Deep  head  of  pronator  radii 
teres 


Posterior  ulnar  recurrent  artery 


Superficial  flexor  muscles, 
turned  back 


Anterior  inlerosseons  artery  and  nerve 
Flexor  profundus  digitorum 
ULNAR  NER  VE 

Ulnar  artery 


Interosseous  membrane  with  cut  edge 
of  pronator  quadratus 


FIG.  123. — THE  LOWKK  PART  OK  TIIK  AXII.I.AKY,  TIIK  P,R.\rm.\i..  AND  THK  RADIAI, 

AND  ULNAR  AKTKKIKS. 
(From  a  dissection  in  the  Hmiterian  Museum.) 


SHOULDER,  ARM,   FOREARM,  AND   HAND. 


179 


the  flexor  carpi  radialis,  the  palmaris  longus,  flexor  sublimis  digitorum,  and  turn 
them  aside,  but  do  not  injure  the  nerves  and  vessels  to  the  same.  Find  the 
ulnar  artery,  and  you  will  see  it  passes  behind  all  these  three  muscles.  Now 
trace  it  a  little  further,  and  see  it  pass  behind  the  flexor  sublimis  digitorum  and 
median  nerve.  Here  you  will  find  it  has  reached  the  ulnar  groove.  Remem- 


Capsular  ligament 
Internal  lateral  ligament 


Tubercle  for  the  flexor  sublimis 

digitorum 
Internal  lateral  ligament 

Brachialis  auticus 
Pronator  radii  teres  (lesser  head) 

Flexor  longus  pollicis  (accessory  head) 


ULNA 


Interosseous  membrane 


Flexor  profundus  digitorum 


Pronator  quadratus 


Anterior  radio-ulnar  ligament 
Internal  lateral  ligament 


GREATER  SIGMOIO  FOSSA 

HEAD  OF  RADIUS 
NECK  OF  RADIUS 
Lower  limit  of  orbicular  ligament 

Oblique  ligament 

BICIPITAL  TUBERCLE 

Oblique  ligament 
Supinator  brevia 

Flexor  sublimis  digitorum 

OBLIQUE  LINE 

RADIUS 

Prouator  radii  teres 


flexor  longus  pollicis 


Pronator  quadratus 


Supinator  longus 
External  lateral  ligament 


Interarticular  flbro-cartilage  Anterior  radio-carpal  ligament 

FIG.   124. — THE  LEFT  ULNA  AND  RADIUS.     (Antero-internal  view.) 

ber  the  course  :  behind  the  median  nerve  and  all  the  muscles  originating  from 
the  inner  condyle,  except  the  flexor  carpi  ulnaris. 

The  radial' s  course  (Fig.  117):  You  will  find  it  very  superficial.  It  begins 
at  the  bifurcation  of  the  brachial  artery  in  the  cubital  fossa.  Now  demonstrate 
the  fact  that  this  artery  lies  on  :  (i)  Biceps  tendon  ;  (2)  supinator  brevis  ;  (3) 
flexor  sublimis  digitorum  ;  (4)  pronator  radii  teres  ;  (5)  flexor  longus  hallucis  ;  (6) 
pronator  quadratus.  These  structures  form  the  floor  of  the  radial  groove. 

The  flexor  sublimis  digitorum  (Fig.  122)  is  brought  into  view  by  turning 


i8o 


PR  A  CTICAL    ANA  TO  MY. 


the  above  muscles  well  aside.  You  will  see  the  radial  artery  lying  on  its  outer 
part ;  the  ulnar  artery  and  median  nerve  above,  passing  behind  the  arch  connect- 
ing the  two  heads  of  the  flexor  sublimis  digitorum  muscle.  This  muscle  has  three 
heads:  (i)  A  condylar,  arising  from  the  inner  condyle  of  the  humerus  ;  (2)  a 


Bleep 


Muscles  of  the  first  and  second 
layers 


Flexor  profundus  digitorum 


Pronator  quadratus 


Flexor  carpi  ulnaris 


Brachio-radialis 


Brachialis  anticus 

Extensor  carpi  radialis  longior 

—  Supinator  brevis 


flexor  longus  pollicis 


Brachio-radialis 


—  Extensor  ossis  metasarpi  pollicis 


Extensor  brevis  pollicis 


FIG.   125. — FRONT  OK  TIIK  FOREARM:  THIRD  LAYER  OF  MUSCLES. 


coronoid,  from  the  coronoid  process  of  the  ulna  ;  (3)  a  radial  head,  from  the 
oblique  line  of  the  radius.  (Fig.  124.)  Cut  the  radial  origin,  and  turn  the 
muscle  toward  the  ulna,  without  injury  to  the  radial  artery,  and  see:  (i)  The 
median  perve,  on  the  under  surface  of  the  muscle;  (2)  the  insertion  of  the 
brachialis  anticus  muscle  into  the  base  of  the  coronoid  process  of  the  ulna;  (3) 


SHOULDER,  ARM,   FOREARM,  AND  HAND. 


181 


the  origin  of  the  flexor  longus  pollicis  muscle  ;  (4)  the  origin  of  the  flexor  pro- 
fundus  digitorum  ;  (5)  the  anterior  interosseous  artery  and  nerve  on  the  inter- 
osseous  membrane,  but  lying  deeply  between  two  muscles — the  flexor  profundus 
digitorum  and  the  flexor  longus  pollicis. 

The  Median  Nerve  and  its  Branches. — Take  the  nerve  up,  and  you  can 
easily  trace  muscular  branches   with  the  forceps  to  all  the  muscles  on  the  front 


Pectoralis  minor 


Coraco-brachialis 


Long  head  of  triceps 


Inner  head  of  triceps 


Brachialis  anticua 


Semilunar  fascia 


Tendons  of  insertion  of  pec- 
toralis  major  and  deltoid 


Outer  head  ct  triceps 


-     Brachialis  anticua 


Extensor  carpi  radialis 
longior 


Brachi  o  -rad  i  alis 


FIG.  126. — SUPERFICIAL  VIEW  OK  THE  FRONT  OK  THE  UPPER  ARM. 


part  of  the  forearm  except  the  flexor  carpi  ulnaris  and  half  of  the  flexor  profundus 
digitorum  muscles  ;  the  flexor  carpi  ulnaris  and  the  ulnar  half  of  the  flexor 
profundus  digitorum  muscles  are  supplied  by  the  ulnar  nerve.  You  will  observe 
that  some  of  the  branches  of  this  nerve  are  given  off  above  the  articulation. 
(Fig.  123.)  Remember,  the  shape  of  a  muscle  is  an  index  to  nerve  distribution. 
See  introductory  chapter. 


182 


PR  A  CTICAL  ANA  TO  MY. 


The  ulnar  nerve  (Fig.  123)  you  have  already  seen  in  the  ulnar  groove  with 
its  accompanying  artery  and  venae  comites.  Now  see  how  it  gains  this  groove. 
Trace  it  behind  the  inner  condyle,  between  the  condylar  and  olecranon  heads  of 
the  flexor  carpi  ulnaris  muscle.  Trace  its  branches  to  this  muscle  and  to  the 
ulnar  half  of  the  flexor  profundus  digitorum.  ' 

The  following  muscles  remain  to  be  dissected  (Fig.  125)  : 

i.   The  flexor  profundus  digitontin,  on  the  ulnar  side. 


Pectoralis  min 


Short  head  of  bice 


Coraco-brachialis 


Long  head  of  triceps 


Long  head  of  bicer 


^—3 Insertion  of  pectoralis  major 


Inner  head  of  triceps 


Internal-intermuecular  septum 


Brachialis  anticus 


S&ML    Outer  part  of  brachialis  anticug 


Insertion  oi  biceps 


FIG.  127. — I)KKi'  VIK\V  OF  run  FRONT  01--  TIIK  I'ITKK  ARM. 


2.  The  flexor  longus  po/licis,  on  the  radial  side. 

3.  The  pronator  radii  quadrat  us. 

4.  The  sjtpinator  radii  brcris. 

You  are  expected  to  dissect  these  muscles  and  study  critically  their  specific 
attachments  to  bone,  and  make  your  dissection  tally  with  the  origins  as  indicated 
on  the  hones  in  figure  124. 

The  flexor  profundus  digitorum  is  seldom  well  learned,  because  students 


SHOULDER,   AR.\f,   FOREARM,   AND   HAND. 


183 


forget  its  aponeurotic  origin.  The  muscle  originates  (i)  from  the  anterior  sur- 
face, upper  two-thirds  of  the  ulna  ;  (2)  from  the  upper  three-fourths  of  the 
posterior  border  of  the  ulna,  with  the  flexor  carpi  ulnaris  and  extensor  carpi 
ulnaris  muscles.  This  latter  is  called  the  aponeurotic  origin.  Trace  nerves  to 
this  muscle  from  the  median  and  ulnar. 


FIG.  128. — DEEP  MUSCLES  OF  PALMAR  ASPECT  OF  FOREARM. 

Lower  portion  of  triceps.  2,  2.  Attachments  of  pronator  radii  teres.  3.  Attachment  of  flexor  carpi 
radialis,  palmaris  longus,  and  flexor  sublimis  digitorum.  3' '.  Tendon  of  biceps.  3" '.  Tendon  of 
brachialis  anticus.  4,  4.  Flexor  carpi  ulnaris.  5.  Supinator  longus.  6.  Its  distal  attachment.  7. 
Supinator  brevis.  7'.  Extensor  carpi  radialis  longior.  8,  8.  Extensor  ossis  metacarpi  pollicis.  9. 
Flexor  profundus  digitorum.  10.  Its  four  tendons.  II.  Tendon  for  index  finger.  12,  12.  Tendon 
for  middle  finger.  13.  Tendon  of  flexor  sublimis.  14.  Tendon  of  flexor  profundus  for  little  finger. 
15,  15.  Lumbricales.  16,  16.  Attachments  of  abductor  brevis.  17.  Opponens  pollicis.  18.  Flexor 
brevis  pollicis.  19.  Adductor  pollicis.  20.  Flexor  longus  pollicis.  21.  Its  tendon.  22,  22. 
Attachments  of  flexor  brevis  and  adductor  minimi  digiti.  23.  Opponens  minimi  digiti. 


Detach  the  extreme  upper  origin  of  this  muscle  and  study  (i)  the  insertion 
of  the  brachialis  anticus  ;  (2)  the  lesser  or  coronoid  head  of  the  pronator  radii 
teres  ;  (3)  the  accessory  head  of  the  flexor  longus  pollicis  ;  (4)  the  coronoid  origin 
of  the  flexor  sublimis  digitorum. 


1 84 


PRACTICAL  ANATOMY. 


The  Pronator  Quadratus. — Observe  the  anterior  interosseous  nerve  termin- 
ating in  this  muscle.  Detach  the  muscle  from  its  ulnar  origin,  turn  the  same  aside, 
and  see  the  anterior  interosseous  artery  piercing  the  membrane  and  gaining  the 
posterior  surface  ;  also  see  the  anastomosis  between  a  branch  of  this  artery  and 
the  anterior  carpals. 


HEAD 


LESSER  TUBEROSITY 
Subscapularis 

Capsular  ligament 


Coraco-brachialis  brevis 
(Rotator  burner!) 

BICIPITAL  GROOVE 


GREATER  TUBEROSITY 

Transverse  humeral  ligament 


Fourth  head  of  biceps 


Coraoo-brachialis 


Third  head  of  bicepe 


Braehialis  anticus 


Coraco-brachialis 

SUPRACONDYLOID  PROCESS 


Pronator  radii  teres 


Capsular  ligament 
CORONUID  FOSSA 


INTERNAL  CONDYLE 
Internal  lateral  ligament 


TROCHLEA 


ROUGH  SURFACE  FOR  deltoid 


THE  EXTERNAL  CONDYLAR  RIDGE 


RADIAL  DEPRESSION 

EXTERNAL  CONDYLE 
CAPITELLUM 


FIG.  129. — THK  LEFT  HU.MKKI  s  \\nii  A  SITK  \OI\I>YI,<III)  PROCESS  AND  SOME  IRREGUI  \K 
MUSCLE  ATTACHMENTS.      (Anterior  view.) 


The  Flexor  Longus  Pollicis  (Fig.  124). — Notice  and  demonstrate  on  your 
dissection  that  the  origin  of  this  muscle  is  limited  above  by  the  tuberosity  and 
oblique  line  of  the  radius  ;  that  the  lower  part  of  the  same  is  limited  by  the 
pronator  quadratus,  the  inner  by  the  interosseous  membrane.  Trace  this  muscle 


SHOULDER,  ARM,  FOREARM,   AND  HAND.  185 

under  the  anterior  annular  ligament,  and  between  the  two  heads  of  the  flexor  brevis 
pollicis,  to  the  base  of  the  distal  phalanx  of  the  thumb,  where  it  is  tendinously 
inserted. 

You  are  to  study  the  radial  oblique  line,  and  let  your  dissections  show 
the  following  points  : 

1.  It  terminates  above  in  the  bicipital  tuberosity,  and  into  this  tuberosity  is 
inserted  the  tendon  of  the  biceps  muscle. 

2.  It   terminates  below  in  a  round  depression,  and  into  this  is  inserted  the 
pronator  radii  teres  muscle.      (Fig.  128.) 

3.  It  has    three   lips  :   an  outer,  into  which   is  inserted  the  supinator  brevis 
muscle  ;    a  middle  lip,  that  gives  origin  to  the  radial  head  of  the  flexor  sublimis 
digitorum,  and  location  to  the  nutrient  foramen  of  the  radius  ;  an  inner  lip,  that 
gives  origin  to  the  flexor  longus  pollicis.     (Fig.  124.) 

THE  FOREARM  FLEXORS. 

In  the  order  of  their  strength  they  are  as  follows  : 

1 .  The  musculus  biceps  cubiti  or  biceps  muscle. 

2.  The  musculus  bracliio-radialis  or  supinator  longus  muscle. 

3.  The  musculus  bracJdalis  anticus — very  broad  and  fleshy. 
Dissect  and  study  the  biceps  with  reference  to  : 

1.  Its  origin  by  a  coracoid  or  short,  and  a  scapular  or  long  head. 

2.  Its  insertion  by  a  tendon  and  by  an  aponeurosis. 

3.  Its  fusiform  belly  and  the  rule  for  the  nerve-supply  of  muscles. 

4.  Its  inferior,  external,  and  internal  relations. 

5.  Its  synergists  and  antagonists,  and  nerve-supply. 

6.  Its  limiting  intermuscular  fasciae. 

7.  Its  fibrous  arch  and  the  rule  for  fibrous  arches. 

The  biceps  (Fig.  126)  you  have  found  inserted  aponeurotically,  by  the  bicip- 
ital or  semilunar  fascia,  into  the  deep  fascia,  over  the  pronator  radii  teres  muscle. 
It  is  tendinously  inserted  into  the  bicipital  tuberosity  of  the  radius.  It  arises 
by  two  heads,  called  long  and  short.  The  long  head  arises  from  the  bicipital 
tubercle,  above  the  glenoid  cavity  of  the  scapula;  it  passes  under  the  transverse 
humeral  ligament  of  the  shoulder,  between  the  greater  and  lesser  tuberosities  of 
the  humerus,  in  the  bicipital  groove.  The  short  head  you  will  find  arising  from 
the  apex  of  the  coracoid  process  of  the  scapula,  with  the  coraco-brachial  muscle. 
These  two  heads  of  the  biceps  are  connected  by  a  fibrous  arch.  See  rule  for 
fibrous  arches  in  the  introductory  chapter.  The  biceps  muscle  rests  on  the  brachi- 
alis  anticus  muscle.  Under  the  biceps  muscle  you  will  find  the  musculo-cuta- 
neous  nerve  which  supplies  it  and  also  the  brachialis  anticus,  coraco-brachial, 
and  supinator  longus  muscles.  Externally  are  the  deltoid  and  triceps  and 
pectoralis  major.  Internally  are  the  triceps,  the  latissimus  dorsi,  teres  major,  and 
coraco-brachial  muscles.  Lift  the  biceps  from  its  bed,  pull  the  same  outward, 
and  you  will  expose  the  brachialis  anticus  muscle  below.  In  the  groove,  between 
the  triceps  and  the  inner  part  of  the  biceps,  are  to  be  found  the  large  branches  of 
the  brachial  plexus  and  the  brachial  artery  and  its  venae  comites. 

The  brachio-radialis  or  supinator  longus  muscle  (Fig.  128)  arises  from  the 
upper  two-thirds  of  the  outer  condylar  ridge  of  the  humerus.  (Fig.  129.)  It  is 
inserted  into  the  base  of  the  radial  styloid  process.  It  has  the  double  function  of 
flexion  and  supination.  Trace  to  it  nerves  from  the  flexor  trunk,  the  musculo- 
cutaneous,  and  from  the  extensor  trunk,  the  musculo-spiral. 

The  brachialis  anticus  (Fig.  127)  arises  from  the  outer  and  inner  surfaces  of 
the  humerus,  limited  above  by  the  insertion  of  the  deltoid  and  coraco-brachial 
muscles.  (Fig.  129.)  Its  insertion  you  have  already  seen  into  the  coracoid  pro- 


1 86  PRACTICAL    ANATOMY. 

cess  of  the  ulna.  Its  nerve-supply  comes  from  the  musculo-cutaneous.  This 
muscle  and  the  preceding  one  act  synergistically'  with  the  biceps  as  flexors  of 
the  forearm  ;  they  are  all  three  antagonized  by  the  triceps. 

The  middle  one-third  of  the  humerus  (Fig.  1 29)  shows  the  following  muscles 
exerting  traction:  (i)  The  brachialis  anticus  ;  (2)  the  deltoid;  (3)  the  coraco- 
brachial ;  (4)  the  upper  and  lower  humeral  heads  of  the  triceps,  on  the  posterior 
surface. 

The  capsule  of  the  elbow  may  now  be  studied.  Remove  the  insertions  of 
the  biceps  and  brachialis  anticus,  and  expose  and  cut  through  the  anterior  liga- 
ment of  the  elbow-joint. 


THE  ANTERIOR  REGION  OF  THE  SHOULDER. 

Dissection  of  this  region  must  be  preceded  by  a  review  of  its  osteology. 
Remember,  the  surgical  importance  of  the  shoulder-joint  is  second  to  none. 

The  Scapula. 

Locate,  classify,  and  describe  geometrically  this  done. 

It  is  located  on  the  upper,  posterior,  and  outer  aspect  of  the  thorax,  limited 
above  by  the  second  and  below  by  the  seventh  rib.  It  is  a  flat  bone.  It  has  a 
dorsal,  or  posterior,  and  a  ventral,  or  anterior,  surface.  It  has  superior,  axillary, 
and  vertebral  borders  ;  an  anterior,  a  posterior  superior,  and  a  posterior  inferior 
angle.  It  has  a  spine,  a  coracoid,  and  an  acromion  process. 

Give  the  importance  of  the  following  parts  of  the  scapula  in  practical  anatomy  : 

The  anterior  angle,  or  head,  articulates  with  the  humerus. 

The  anatomical  neck  gives  attachment  to  the  capsular  ligament. 

The  surgical  neck  is  often  the  seat  of  fracture. 

The  spine  divides  the  dorsum  into  supra-  and  infraspinous  fossae. 

The  posterior  inferior  angle  is  crossed  by  the  latissimus  dorsi  muscle. 

The  supraspinous  fossa  is  occupied  by  the  supraspinatus  muscle. 

The  infraspinous  fossa  is  occupied  by  the  infraspinous  muscle. 

The  subscapular  fossa  is  occupied  by  the  subscapularis  muscle. 

The  superior  border  has  the  suprascapular  foramen  and  omo-hyoid  muscl 

The  suprascapular  foramen  transmits  the  suprascapular  nerve. 

The  coracoid  process  gives  attachment  to  three  muscles  and  three  ligaments. 

The  acromion  process  gives  attachment  to  the  trapezius  and  deltoid. 

The  scapular  notch  transmits  the  infraspinous  vessels  and  nerve. 

The  scapular  angle  is  the  deepest  part  of  the  subscapular  fossa. 

Name  the  muscles  and  ligaments  you  arc  expected  to  find  attaclicd  to  tJic  cora- 
coid process  of  the  scapula. 

The  short  head  of  the  biceps,  the  coraco-brachialis,  and  the  pectoralis  minor 
muscles  ;  the  coraco-acromial,  conoid,  and  trapezokl  ligaments. 

The  supra-  and  infraglcnoid  tubercles  arc  where  situated  and  liow  occupied  / 

They  arc  immediately  above  and  below  the  glenoid  cavity  of  the  scapular 
head  respectively  :  the  supraglenoid  tubercle  gives  origin  to  the  long  head  of  the 
biceps  ;  the  infraglenoid  to  the  long  head  of  the  triceps  muscle. 

II  'hat  can  YOU  say  specifically  about  flic  origins  of  the  tlircc  muscles  from  tlic 
t/ircc  scapular  fossce  ? 

The  whole  of  the  fossa  in  each  case  does  not  give  origin  to  the  muscle,  only 
tin-  outer  two-thirds  thereof.  The  one-third  next  the  shoulder  is  occupied  by 
fatty  connective  tissue,  vessels,  and  nerves. 


SHOULDER,  ARM,  FOREARM,  AND  HAND.  187 

Name  the  muscles  attaclicd  to  tlie  middle  lip  of  the  axillary  border  of  the 
scapula. 

The  triceps,  teres  minor,  and  teres  major.  The  rule  governing  the  relation 
of  anatomical  minors  to  majors  is  :  minors  occupy  a  high,  majors  a  low,  level. 

Name  the  bony  points  of  t/ie  scapula  traversed  by  a  fracture  of  the  so-called 
surgical  neck  of  the  scapula,  and  the  important  structures  endangered  by  sucli  a 
fracture. 

The  suprascapular  notch,  in  which  is  the  suprascapular  nerve,  and  above 
which  are  the  suprascapular  vessels  ;  the  scapular  notch,  in  which  are  found  the 
vessels  and  nerves  for  the  infraspinatus  muscle  ;  the  scapular  angle,  in  which  are 
the  vessels  and  nerves  for  the  subscapularis  muscle. 

Hoiv  is  the  anterior  lip  of  the  vertebral  border  of  the  scapula  occupied  ? 

By  the  subscapularis  and  serratus  magnus  muscles.  The  latter  muscle  de- 
presses the  shoulder-girdle,  being  antagonistic  to  the  trapezius  and  levator  anguli 
scapulae  muscles. 

Name  the  muscles  inserted  into  t/ie  middle  lip  of  the  vertebral  border  of  the 
scapula. 

The  levator  anguli  scapulae,  rhomboideus  minor,  rhomboideus  major.  Notice 
here  the  high  origin  of  the  minor,  and  note  the  rule  previously  mentioned 
governing  the  relation  of  anatomical  majors  and  minors. 

How  are  the  three  lips  of  the  spine  of  the  scapula  occupied  ? 

The  superior  by  the  insertion  of  a  part  of  the  trapezius  ;  the  inferior  by  origin 
of  part  of  the  deltoid  ;  the  middle  is  subcutaneous,  and  is  also  called  the  crest. 

The  Clavicle. 

Name  parts  of  this  bone  of  importance  in  practical  anatomy. 

The  sternal  end,  articulating  with  the  manubrium. 

The  acromial  end,  articulating  with  the  acromion. 

The  anterior  surface  of  the  inner  two-thirds  of  the  bone. 

The  superior  surface  of  the  outer  one-third  of  the  bone. 

The  inferior  surface  of  the  bone. 

What  is  the  importance  of  the  superior  surface  of  the  outer  one-third  of  the 
clavicle  ? 

The  attachment  of  the  trapezius  muscle  posteriorly,  and  the  deltoid  anteriorly. 

What  is  the  importance  of  the  anterior  surface  of  the  inner  two-thirds  of  the 
clavicle  f 

The  origin  of  the  pectoralis  major  and  the  sterno-cleido-mastoid  muscles. 

What  can  you  say  of  the  posterior  surface  of  the  clavicle  ? 

It  forms  an  arch  over  the  brachial  plexus  and  subclavian  artery  and  vein. 

Tell  what  you  expect  to  find  on  the  inferior  surface  of  the  clavicle. 

The  subclavius  muscle,  in  a  groove  in  the  middle  one-third  ;  the  origins  of 
the  sterno-hyoid  and  sterno-thyroid  muscles,  and  the  impress  for  the  rhomboid 
or  costo-clavicular  ligament  ;  the  oblique  line  for  the  trapezoid  ligament  and  a 
small  tuberosity  for  the  conoid  ligament. 

1.  Intermuscular  groove  between  the  pectoralis  major  and  deltoid. 

2.  The  pectoralis  major  muscle  and  pectoral  fascia. 

3.  Suprasternal  and  supraclavicular  nerves. 

4.  The  cephalic  vein  and  descending  branch  of  acromio-thoracic  artery. 

5.  The  pectoral  and  deltoid  origins  on  the  clavicle. 

6.  The  perforating  branches  of  the  internal  mammary  artery. 

7.  The  axillary  space  geometrically. 


i88 


PRACTICAL  ANATOMY. 


THE  AXILLARY  SPACE. 


1.  A  Base. — Skin,  superficial,  and  deep  fascia,  called  axillary. 

2.  An  Apex. — Formed  by  clavicle,  first  rib,  and  scapula. 

3.  Anterior  Border. — Pectorales  major  and  minor,  and  clavi-pectoral  fascia. 


Deltoid 


Biceps 


Teres  major 


Aponeurosis  of  external  oblique 


External  intercostal 


FK;.   130. — THE  PECTORAI.IS  MAJOR  AND  DELTOID. 


Deltoid 


Pectoralis  major 


Trapezius 


Sterno-maatoid 
POSTERIOR 
FH;.    131.— THE  I.KIT  < 'I.AVICI.K.      \  Superior  surface.) 


4.  Interior  Border. — Ribs,  intercostal  spaces  (six),  and  serratus  magnus. 

5.  Anterior  Thoracic  Angle. — Long  thoracic  artery. 

(>.  Interior  Thoracic  Angle. — Subscapular  artery  and  Bell's  nerve. 

7.  External  or  Humeral  Angle. — Axillary  artery  and  nerves. 


SHOULDER,  ARM,   FOREARM,  AND  HAND. 


189 


8.  Contents. — Axillary    connective   tissue  and    glands  ;    the   axillary  artery 
and  vein  and  their  branches  ;  the  large  branches  of  the  brachial  plexus. 

9.  The  posterior  boundary  is  formed  by  the  subscapular,  teres  major,  and  latis- 
simus  dorsi  muscles. 

The  cephalic  vein  and  descending  branch  of  the  acromio-thoracic  artery. 
The  vein  (Fig.  105)  is  the  guide  to  the  groove.  The  groove  is  the  boundary- 
line  between  the  clavicular  origins  of  the  pectoralis  major  and  deltoid  muscles. 
The  vein  opens  into  the  subclavian. 

The  Pectoralis  Major  Muscle. — Remove  the  skin  and  find  in  the  super- 
ficial fascia  two  cutaneous  nerves — the  supraclavicular  and  suprasternal  ;  the 
one  supplying  the  skin  over  the  deltoid  is  the  supraacromial.  These  are  the 
descending  branches  from  the  superficial  part  of  the  cervical  plexus. 


Subclavius    muscle 


First  Rib 


CUT  END  OF  CLAVICLE 


Costo-coracoid 
ligament 


Cephalic  rein 

. I rroin  io-thoraeic  artery 

Xti/H-riii1'  flinnii-ic  ai-ten/ 
Clavi-pectoral  fascia 


l>n*TI-:RIOR  THOR- 
ACIC .VAY.M7-; 


FIG.   132. — THE  CLAVI-PECTORAL  FASCIA. 


The  deltoid  aponeurosis  is  the  deep  fascia  covering  the  muscle  of  the  same 
name.  It  is  continuous  with  the  pectoral  in  front,  the  infraspinous  behind,  and 
the  axillary  below. 

The  Deltoid  Muscle. — Detach  this  muscle  from  the  clavicle  (Fig.  131)  and 
acromion  process  of  the  scapula.  Turn  the  muscle  outward.  Follow  the  muscle 
to  its  insertion  into  the  deltoid  ridge,  on  the  outer  surface  of  the  humenis. 
(Fig.  127.)  Cut  this  insertion  and  turn  the  muscle  farther  back,  so  as  to  expose 
the  insertion  of  the  pectoralis  major. 

The  Pectoralis  Major. — Remove  the  fascia  with  a  sharp  scalpel.  Place 
the  arm  at  a  right  angle  to  the  body  ;  notice  that  the  deep  fascia  you  are  now 


190 


PR  A  CTICAL  ANA  TOMY. 


removing  is  continuous  with  the  deep  fascia  covering  the  base  of  the  axilla. 
Observe  the  sternal  and  clavicular  origins  of  the  muscle.  See  some  cutaneous 
nerves  and  arteries  piercing  the  thoracic  wall,  near  the  sternum.  (Fig.  132.)  The 
arteries  are  the  perforating  branches  from  the  internal  mammary  ;  the  nerves  are. 
the  anterior  cutaneous  branches  of  the  intercostals.  Cut  the  insertion  of  the  pec- 
toralis  major.  Note  that  the  fibres  that  form  the  lower  margin  of  the  tendon 
of  the  muscle  are  inserted  high  ;  those  that  form  the  upper  border  of  the  muscle 
are  inserted  low,  into  the  posterior  lip  of  the  bicipital  groove  of  the  humerus. 

Now  cut  the  clavicular  origin  of  the  pectoralis  major,  and  carefully  pull  the 
muscle  forward.  On  the  under  surface  you  will  see  the  external  anterior  thoracic 
nerve,  a  branch  of  the  outer  cord  of  the  brachial  plexus,  coming  through  the 
pectoralis  minor  muscle  to  supply  the  major  pectoral  muscle.  Now  cut  the 
sternal  origin  of  the  pectoralis  major  and  turn  the  same  out  of  the  way  without 
injuring  the  nerve -supply. 


above    /  ^       shove 
r       7  —  f&Jai/ 
/         Aeti 


Mylo-hy 
Old  fascii 

Digastric  fascia 
"~^  Submaxillary  fascia 
~~~  Stylo-mandibular  ligament 
Masseteric  fascia 
Parotid  fascia 


•CUT  END  OF  CLAVICLE 


Subclavius  sheath 
Costo-eoracoid  ligament 
Clavi-pectoral  fascia 

Minor  pectoral  sheath 

-   Axillary  or  suspensory  fascia 

FIG.   133.  —  To  SHOW   SCHEMATICALLY  THE  DISTRIBUTION  OF  THE  DEEP  CERVICAL   FASCIA  AI;U\I. 

AND    BELOW   THE   CLAVICLE. 


Four  very  important  structures,  easily  understood,  quickly  developed,  and 
seldom  appreciated  by  the  student,  are  now  before  you  : 

1.  The  subclarius  muscle  and  its  sheath  of  cervical  fascia. 

2.  The  costo-coracoid  ligament,  a  part  of  subclavius  sheath. 

3.  The  clavi- pectoral  fascia — triangular  and  thin. 

4.  The  pectoralis  minor  muscle  and  its  sheath. 

The  third  layer  of  deep  cervical  fascia  passes  behind  the  clavicle,  forms  a 
sheath  for  the  subclavius  muscle,  and  unites  along  the  lower  margin  of  the  sub- 
clavius muscle  to  form  a  thick,  strong  band* — the  costo-coracoid  ligament.  The 
fascia  then  bridges  the  triangular  space  between  the  subclavius  muscle  and  the 
pectoralis  muscle,  under  the  name  of  clavipectoral  fascia.  (Fig.  132.)  At  this 
point  the  fascia  again  delatninates,  to  form  a  sheath  for  the  pectoralis  minor 
muscle.  At  the  lower  border  of  this  muscle  the  fascia  is  continuous  with  the 
deep  fascia  of  the  base  of  the  axilla,  and  is  known  technically  as  the  axillary 


SHOULDER,   ARM,   FOREARM,  AND  HAND. 


191 


fascia.  Let  figure  133  illustrate  in  this  connection  schematically  the  distribution 
of  the  four  layers  of  deep  cervical,  both  below  and  above. 

It  will  be  seen  from  figure  133  that  the  first  layer  of  deep  cervical  fascia  is 
specialized  above  the  clavicle  as  parotid  fascia,  masseteric  fascia,  stylo-mandibular 
ligament,  submaxillary  fascia,  digastric  fascia,  and  mylo-hyoid  fascia  ;  below,  the 
first  layer  is  attached  to  the  clavicle.  The  second  layer  is  attached  above  to 
the  hyoid  bone,  having  ensheathed  the  depressor  muscles  of  this  bone  (Fig.  24)  ; 
below,  this  fascia  is  attached  to  the  clavicle.  The  fourth  layer  is  connected  to 
the  occipital  bone  and  the  muscles  in  front  of  the  vertebral  column. 

The  third  layer  is  of  greatest  importance  surgically,  and  the  most  complex. 
Passing  behind  the  clavicle  and  sternum,  this  layer  divides  into  a  thoracic  por- 
tion, which  expands  to  form  the  fibrous  part  of  the  pericardium,  and  also  into  an 
axillary  portion,  which  has  been  previously  described. 

Pus  formed  between  the  first  and  second  layers  of  deep  cervical  fascia  would 
be  arrested  at  the  clavicle.  Pus  formed  in  the  carotid  sheath  might  easily  find 
its  way  to  either  the  axilla  or  pericardium.  The  student  must  take  schematic 
representations  with  a  grain  of  allowance,  remembering  that  fascial  development, 
like  muscular  development,  is  a  variable  thing,  and  in  some  cases  would  not 
direct  pus  whither  the  scheme  might  indicate.  After  all,  the  scheme  just 


POSTERIOR 


Oblique 

line  for 

Capsular        trapezoid    Tuberosity  for 
ligament       ligament    conoid  ligament 


Rhomboid 
ligament  and 
Sterno- 
hyoid     Sterno-thyroid 


FACET  FOR  FIRST 
COSTAL  CARTILAGE 


STERNAL  FACET 


ACROM1AL  FACET 


Pectoralis  major 
ANTERIOR 


FIG.   134. — THE  LEFT  CLAVICLE.     (Inferior  surface.) 

given  is  to  teach  that  many  fascial  entities  are  definitionally  only  a  certain  seg- 
ment of  deep  cervical  fascia.  For  example  :  What  is  the  subclavius  sheath  ?  It 
is  that  part  of  the  third  layer  of  the  deep  cervical  fascia  that  invests  the  sub- 
clavius muscle.  What  is  the  parotid  fascia  ?  It  is  that  part  of  the  first  layer  of 
deep  cervical  fascia  which  is  continued  above  the  angle  of  the  jaw  to  form  a 
capsule  for  the  parotid  gland.  See  in  the  introductory  chapter  the  rule  for 
naming  specialized  modifications  of  deep  fascia  in  any  region  of  the  body. 

The  subclavius  muscle  arises  from  the  first  rib,  near  the  sternum,  and  is  in- 
serted into  the  groove  on  the  under  surface  of  the  clavicle  (Fig.  134),  occupying 
the  middle  two-fourths  of  the  surface.  It  is  surrounded  by  a  sheath — the  sub- 
clavian  sheath. 

The  pectoralis  minor  muscle  arises,  as  a  rule,  from  the  third,  fourth,  and 
fifth  true  ribs,  and  is  inserted  into  the  anterior  border  of  the  coracoid  process  of 
the  scapula.  Its  nerve  is  the  internal  anterior  thoracic,  a  branch  of  the  inner 
cord  of  the  brachial  plexus. 

The  clavi-pectoral  space  is  the  triangular  interval  you  see  between  the  upper 
border  of 'the  pectoralis  minor  muscle  and  the  subclavian  muscle.  As  you  will 
see  on  your  cadaver,  this  space  is  filled  in  by  a  delicate  fascia,  attached  above  to 
the  subclavius  muscle  and  below  to  the  pectoralis  minor  muscle.  This  is  the 
clavi-pectoral  fascia.  (Fig.  132.) 


192 


PRACTICAL  ANATOMY. 


THE  AXILLA,  OR  AXILLARY  SPACE. 

The  axilla,  or  axillary  space,  is  of  interest  anatomically  because  important 
surgical  operations  are  performed  here.  Armpit  and  axilla  are  not  synonymous 
terms.  The  physician  places  a  clinical  thermometer  in  the  armpit — not  in  the 
axilla.  The  axillary  lymphatic  glands  become  secondarily  enlarged  in  cases  of 
infection,  and  may  require  extirpation.  The  head  of  the  humerus  may  become 
dislocated  into  the  axilla  and  require  reduction.  Pus  may  form  in  the  neck  and 
find  its  way  to  the  axilla  and  make  its  liberation  incumbent.  A  wound  of  the 
axillary  artery  makes  its  ligation  a  necessity.  Amputation  at  the  shoulder-joint 
is  sometimes  done. 

The  apex  of  the  axilla  or  inlet  has  bony  boundaries:  (i)  The  outer  surface  of 
the  first  rib  ;  (2)  the  clavicle  ;  (3)  the  superior  costa  or  superior  border  of  the  scapula. 
It  is  by  the  apex  that  this  space  communicates  with  the  thorax  and  neck. 


Upper  part  of 
serratus  magnuc 


Middle  part 


Lower  part 


FIG.  135. — SERRATUS  MAGNUS.     THE  INNER  \\AI.I    OF  THE  AXII.I.A. 

The  base  of  the  axilla  is  formed  by  the  skin,  the  superficial  and  the  deep 
fascia.  The  deep  fascia  in  this  locality  is  known  specifically  as  axillary  fascia  ; 
it  is  also  called  suspensory  fascia.  The  deep  fascia  is  a  derivative  of  the  third 
layer  of  the  deep  cervical  fascia,  passing  under  the  clavicle.  In  front  it  is  con- 
tinuous with  the  pectoral  fascia;  behind,  with  the  fascia  covering  the  latissimus 
dorsi  muscle. 

The  anterior  boundary  is  formed  by  the  skin,  fascia:,  pectorales  major  and 
minor  muscles,  and  clavi-pectoral  fascia.  This  boundary  is  very  well  defined. 

The  posterior  boundary  is  formed  by  the  subscapularis,  the  teres  major,  and 
latissimus  dorsi  muscles. 


SHOULDER,  ARM,  FOREARM,  AND  HAND.  193 

The  inner  boundary  is  formed  by  six  or  eight  ribs,  their  intercostal  muscles 
and  fasciae,  and  six  serrations  of  the  serratus  magnus  muscle.  (Fig.  132.) 

The  angles  are  three  in  number,  and  the  surgical  importance  of  each  is  that 
in  these  angles  are  found  some  structure  or  structures  to  be  avoided,  or  reached 
in  surgical  operations,  (i)  The  anterior  thoracic  angle  contains  the  long  thoracic 
artery  ;  (2)  the  posterior  thoracic  angle  contains  the  subscapular  artery  and  the 
external  phrenic  nerve  ;  (3)  the  outer  or  Innncral  angle  contains  the  axillary 
artery  and  nearly  all  the  important  branches  of  the  brachial  plexus. 

The  Axillary  Contents. — On  removing  the  anterior  wall  of  the  axilla,  as 
you  may  now  complete  doing,  by  cutting  the  pectoralis  minor  at  its  insertion,  and 
turning  the  same  back,  with  its  attached  clavi-pectoral  fascia,  you  will  see  (i)  a 
mass  of  axillary  connective  tissue  containing  some  fat  and  blood-vessels,  the  alar 
thoracic  vessels,  and  axillary  lymphatic  glands.  In  health  these  glands  are  not 
larger  than  a  small  pea,  and  are  bluish  in  color.  When  diseased,  as  is  frequently 
the  case  in  dissecting-room  material,  they  are  often  very  large  ;  they  may  be  as 


CLAVICLE 

CORACOIO  PROCESS 
Supra-spinatus 


Subscapularis 


Teres  major 
Latissimus  dorsi 


Coraco-brachialis  and  short 
head  of  biceps 

Pectoralis  major 


FIG.   136. — FRONT  VIEW  OF  THE  SCAPULAR  MUSCLES.     THE  POSTERIOR  WALL  OF  THE  AXILLA. 


large  as  a  hazelnut,  or  even  larger.  Each  student  should  visit  every  table  in  the 
room,  when  this  area  is  being  dissected,  to  inspect  the  condition  of  these  glands. 

To  clean  out  the  axilla  means,  in  surgery,  to  remove  the  diseased  axillary 
glands.  This  operation  is  attended  by  slight  hemorrhage.  The  vessels  that 
should  bleed  are  the  alar  thoracics.  These  supply  the  glands  and  fat  in  this 
space.  The  term  unavoidable  hemorrhage  would  be  an  excellent  expression  by 
which  to  designate  the  bleeding  incident  to  the  removal  of  these  glands,  if  this 
expression  were  not  already  the  stereotyped  property  of  obstetric  nomenclature. 

Systematic  Examination  of  the  Walls  and  Contents  of  the  Axillary  Space. 
—  i.  Examine  the  inner  icall  and  find:  (i)  The  outer  surface  of  the  six  upper 
ribs.  (2)  The  serrations  of  the  serratus  magnus  muscle.  (Fig.  135.)  (3)  Coming 
through  two  or  three  intercostal  spaces, — the  second,  third,  fourth, — some  cuta- 
neous nerves  will  be  seen.  These  nerves  cross  the  space  and  seem  to  become  lost 
in  the  mass  of  fat  you  have  just  examined.  These  nerves  are  the  posterior  lateral 
'cutaneous  branches  of  the  intercostal  nerves.  Now  trace  them  out  as  follows  : 
One  passes  out  under  the  pectoralis  major  muscle  to  the  skin  of  this  muscle,  in 
front ;  a  second  passes  out  behind,  around  the  latissimus  clorsi,  to  the  skin  of 
this  muscle  ;  a  third  passes  down  the  center  of  the  space,  joins  a  branch  of  the 


i94 


PR  A  CTICAL   ANA  TOM  Y. 


BRACHIAL  PLEXUS 


HEAD  OF  HUMERUS 
Fectoralis  minor,  turned  back 

MUSCULO-CUTANEOUS  NERVE 

BRANCH   OF  MUSCULO-CUTA- 

NEOUS  TO   MEDIAN  NERVE 

Coraco-brachialiB 


Brachial  artery 

Superior  profunda  artery 
Biceps 


MUSCULO-CUTANEOUS  NERVE  — 

URANCH  OP  MUSCULO-CUTA- 
NEOVS NERVE  TO  BRACHI- 
ALIS  ANTICUS 

Brachialis  anticus 

MEDIAN  NERVE 

Inner  brachial  vena  comes 
MUSCULO-SPIRAL  NERVE 

Radial  recurrent  artery 
Supinator  loiigus 

Superficial  median  vein,  cut  short 


Fronator  radii  feres,  superficial 
head,  cut 


RADIAL  NERVE 


Radial  artery 


Cut  edge  of  flexor  sublimis 
digitorura 


MEDIAN  NER  VE 


Flexor  lougus  polliois 


Subscapularis 
Acromio-lhoracic  artery 
Axillary  artery 
MEDIAN  NERVE 
Subscapular  artery 

Teres  major 
Latissimus  dorsi 

Long  head  of  triceps 
MUSCULO-SPIRAL  NERVE 

)  MUSCULAR  BRANCH  OF 
\     Ml'KCULO-SPIRAL 


Inferior  profunda  artery 


Inner  head  of  triceps 
ULNAR  NERVE 


BM Anaslomolica  marjna  artery 

Internal  intermuscular  septum 


MUSCULAR  BRANCHES  OF 
MEDIAN  NERVE 

Pronator  teres  and  superficial 
flexor  muscles,  turned  back 

A  n!1  rior  ulnar  recurrent  <u i<-rt/ 

Beep  head  of  pronator  radii 
teres 


Posterior  ulnar  recurrent  artery 


Superficial  flexor  muscles, 
turned  back 


Anterior  ititerosxenns  artery  and  nerve 
Flexor  profundus  digitorum 
ULNAR  NERVE 


Interosseous  membrane  with  cut  edge 
of  pronator  quadratus 


IMC.   137. — THK  I.mvKK  PART  OF  THE  AXIIIAKV.    ini.   HK.U  HIM,   AMI   IHK  RADIAL 

AND  Ui-NAR  AKTKKII-.S. 
(From  a  dissection  in  the  Hunterian  Museum.) 


SHOULDER,   ARM,   FOREARM,   AND  HAND.  195 

lesser  internal  cutaneous  nerve  (Wrisberg's),  and  is  distributed  to  the  skin  of  the 
inner  surface  of  the  arm.  This  nerve  is  called  the  intercosto-humeral  nerve.  It 
comes  through  the  second  intercostal  space. 

2.  Examine  the  posterior  wall  (Fig.  136)  and  find  the  (i)  subscapularis  mus- 
cle ;  (2)  teres  major  muscle  ;  (3)  latissimus  dorsi  muscle  ;  (4)  the  three  subscap- 
ular  nerves   supplying  these  muscles.     They  are  branches  of  the  posterior  cord 
of  the  brachial  plexus. 

Notice  while  dissecting  the  posterior  wall  of  the  axilla  the  following  structures 
shown  in  figure  136  :  (i)  The  relation  between  the  insertions  of  the  teres  major 
and  latissimus  dorsi.  Clean  off  the  fascia  and  fat  carefully,  and  see  the  lower 
muscle  crossing  the  higher,  to  be  inserted  above  this.  (2)  Trace  out  and  study 
carefully  the  specific  tendinous  insertion  of  the  pectoralis  major.  (3)  Clean  the 
subscapularis  muscle,  notice  its  nerve-  and  blood-supply,  and  the  relation  of  this 
muscle  to  the  insertion  of  the  serratus  magnus. 

3.  Examine  the  Anterior  Thoracic  Angle. — In  this  angle  you  will  find  the  long 
thoracic  or  external  mammary  artery.   Trace  its  branches  to  the  pectoral  muscles, 
the  serratus  magnus,  the  subscapularis,  and  the  lymphatic  glands. 

4.  Examine  the  Posterior   Thoracic   Angle. — In  this  you  will  find  the  long 
thoracic  nerve  and  the  subscapular  artery.     Trace  branches  from  this  nerve  to  the 
serratus  magnus.      (Fig.  132).     Trace  the  subscapular  artery  to  the  muscles  of 
the  posterior  wall.      Find  its   largest  branch,  leaving  the  axillary  space  by  the 
triangular  space,  between  the  teres  major  and  minor  and  internal  to  the  scapular 
head  of  the  triceps. 

5.  Examine  the  External  or  Humeral  Angle  (Fig.  1 37). — Find  first  the  median 
nerve,  lying  on  the  front  of  the  axillary  artery.     Trace  this   nerve   upward  and 
find  its  inner  and  outer  heads,  from  the  inner  and  outer   cords  of  the  brachial 
plexus. 

The  ulnar  nerve  lies  to  the  inner  side  of  the  axillary  artery.  Trace  this  up 
to  the  inner  cord  of  the  brachial  plexus  ;  also  trace  it  down  behind  the  inner 
condyle  of  the  humerus.  See  where  it  joins  company  with  the  inferior  profunda 
artery. 

The  musculo-cutaneous  nerve  lies  to  the  outer  side  of  the  axillary  artery. 
You  will  find  this  nerve  close  to  the  insertion  of  the  pectoralis  minor.  Trace  it 
through  a  hole  in  the  coraco-brachial  muscle.  It  is  a  branch  of  the  outer  cord  of 
the  brachial  plexus. 

The  musculo- spiral  nerve  lies  behind  the  axillary  artery.  (Fig.  137.) 
Trace  it  downward  and  it  will  soon  disappear  between  the  two  humeral  heads  of 
the  triceps  muscle.  It  is  a  branch  of  the  posterior  cord  of  the  brachial  plexus. 

The  circumflex  nerve  lies  behind  the  axillary  artery.  It  is  a  branch  of  the 
posterior  cord  of  the  brachial  plexus.  It  soon  escapes  to  the  posterior  part  of 
the  shoulder  by  the  quadrangular  space,  with  the  posterior  circumflex  artery. 

The  subscapular  nerves,  three  in  number,  lie  the  most  deeply  of  all  the 
nerves  in  this  region.  They  are  given  off  to  the  muscles  that  form  the  posterior 
boundary  of  the  axillary  space.  The  nerve  to  the  latissimus  dorsi  is  called  the 
long  subscapular. 

The  anterior  thoracic  nerves  are  two  in  number  ;  they  are  called  external 
and  internal.  The  internal  anterior  thoracic  nerve  is  from  the  inner  cord  of  the 
brachial  plexus  ;  it  supplies  the  pectoralis  minor.  The  external  anterior  thoracic 
nerve  is  from  the  outer  cord  of  the  brachial  plexus  ;  it  pierces  the  clavi-pectoral 
fascia  and  goes  to  the  pectoralis  major.  The  internal  anterior  thoracic  nerve  also 
sends  a  branch  to  the  pectoralis  major  muscle.  This  pierces  the  clavi-pectoral 
fascia. 

The  internal  cutaneous  and  lesser  internal  cutaneous  nerves  are  inter- 
nal to  the  axillary  artery.  They  must  not  be  mistaken  for  the  ulnar. 


196  PRACTICAL   ANATOMY. 

The  Axillary  Artery  and  Vein. — This  artery  has  three  stages,  as  follows  : 

1.  First  stage,  from  first  rib  to  the  pectoralis  minor  muscle. 

2.  Second  stage,  behind  the  pectoralis  minor  muscle. 

3.  Third  stage,  below  the  pectoralis  minor  muscle. 

Note  that  the  axillary  vein  lies  internal  to  the  artery  in  all  three  stages  ; 
that  it  receives  two  large  tributaries  :  (i)  the  cephalic,  (2)  the  basilic  veins. 

Branches  of  the  axillary  artery  according  to  stages  : 

First  Stage. — (i)  The  superior  tJwracic  passes  between  the  pectoral  muscles 
to  the  chest  walls.  Trace  branches  from  it  to  these  muscles  and  to  the  thoracic 
walls.  (2)  The  acromio-thoracic  perforates  the  clavi-pectoral  fascia  (Fig.  132), 
and  sends  branches  to  the  deltoid  and  pectoral  muscles.  Its  descending  branch 
you  found  deeply  buried  in  a  groove  with  the  cephalic  vein,  between  the  deltoid 
and  pectoralis  major  muscles. 

Second  Stage. — (i)  Alar  tJwracic  branches  have  been  seen  supplying  the 
axillary  glands  and  fat.  (2)  The  long  tlwracic  you  will  find  in  the  anterior  thoracic 
angle.  Trace  its  numerous  branches  to  all  the  walls  of  the  axillary  space. 

Third  Stage. — (i)  The  anterior  circumflex  artery  you  will  trace  behind  the 
coraco-brachial  and  biceps  muscles.  It  sends  a  branch  to  the  shoulder-joint 
through  the  bicipital  groove.  (2)  The  posterior  circumflex  passes  through  the 
quadrangular  space,  with  the  circumflex  nerve,  to  the  deltoid  muscle  and 
shoulder-joint.  The  space  referred  to  is  bounded  externally  by  the  humerus, 
internally  by  the  scapular  head  of  the  triceps,  superiorly  by  the  teres  minor, 
inferiorly  by  the  teres  major  and  latissimus  dorsi.  (3)  The  subscapular  is  the 
largest  branch  of  the  axillary  artery.  You  will  find  it  in  the  posterior  thoracic 
angle.  It  passes  through  the  triangular  space,  and  takes  the  name  of  dorsalis 
scapulce.  This  space  is  bounded  by  the  triceps  and  the  teres  minor  and  major. 

The  muscles  in  this  locality  are  : 

1.  The  Serratus  Magnus. — This  arises  from  the  outer  surface  of  the  upper 
eight  ribs  by  nine  fleshy  processes.     (Fig.  135.)      It  is  inserted  into  the  anterior 
lip  of  the  vertebral  border  of  the  scapula.     It  is  supplied  by  the  long  thoracic 
nerve,  a  branch  of  the  brachial  plexus.     (Fig.  42.) 

2.  The  Subscapularis  Muscle. — This  arises  from  the  subscapular  fossa  and 
is  inserted  into  the  lesser  tuberosity  of  the  humerus. 

3.  The  teres  major  arises  from  the  middle  lip  of  the  axillary  border  of  the 
scapula.      It  is   inserted  into  the  posterior    lip  of  the  bicipital   groove  of  the 
humerus  with  its  synergist,  the  latissimus  dorsi. 

4.  The  latissimus  dorsi  is  a  muscle  of  the  back,  and  will  be  described  in  the 
proper  place.     The  student  will  now  trace  the  subscapular  nerves,  from  the  pos- 
terior cord  of  the  brachial  plexus  to  the  subscapular,  the  teres  major,  and  the 
latissimus  dorsi  muscles.     Also  study  the  relation  and  manner  of  insertion  of  the 
two  latter  muscles  into  the  humerus. 

The  Brachial  Artery. — This  vessel  begins  as  a  continuation  of  the  axillary 
artery,  at  the  lower  border  of  the  teres  major  muscle.  (Fig.  137.)  It  ends  at 
the  elbow,  by  dividing  into  the  radial  and  ulnar  arteries.  In  its  course  you  can 
show  the  triceps  muscle  on  one  side  and  the  biceps  and  coraco-brachial  on  the 
other  side  of  this  artery.  The  median  basilic  vein  lies  in  front  of  it,  near  the  elbow 
(Fig.  105),  the  bicipital  fascia  intervening.  The  median  nerve  crosses  it  in  the 
middle  of  its  course.  As  you  must  demonstrate  on  your  work,  this  artery  lies 
superficially  in  its  entire  course,  and  may  be  easily  reached  for  compression  or 
operation.  Find  tin-  ulnar  and  internal  cutaneous  nerves,  internal  to  the  artery. 
Examine  every  cadaver  in  the  room  to  find  high  bifurcations  of  the  brachial 
artery. 

The  branches  of  the  brachial  artery  are  : 

I .    The  muscular  hrancJies  to  the  flexor  muscles  of  the  forearm. 


SHOULDER,  ARM,  FOREARM,  AND  HAND.  197 

2.  Tlic  nutrient  artery  to  the  humerus,  about  the  middle.       Find  the  nutrient 
foramen  directed  toward  the  elbow  on  the  inner  surface  of  the  humerus,  near 
the  insertion  of  the  coraco-brachial  muscle. 

3.  Tlie  Superior  Profunda  Artery. — Find  this  artery  on  a  level  with  the  major 
tereal  muscle.      It  accompanies  the  musculo-spiral  nerve  in  the  groove  bearing 
the  same  name.      This  artery  supplies  the  triceps  and  gives  off  an  artery  to  the 
upper  one-third  of  the  humerus.      It  anastomoses  with  the  radial  recurrent,  the 
posterior  ulnar  recurrent,  and  the  posterior  interosseous  recurrent,  and  with  the 
inferior  profunda  and  anastomotica  magna  arteries. 

4.  The  inferior  prof nnda  you  will  find  a  little  below  the  middle  of  the  arm.    It 
joins  the   ulnar  nerve,  accompanies  the   same,  and  terminates  by  anastomosing 
with  the  anastomotica  magna  and  posterior  ulnar  recurrent  arteries. 


THE   THORAX. 


ANTERIOR  AND  LATERAL  WALLS. 

Locate  (i)  the  sternum,  presternum,  mesosternum,  metasternum.  (2)  The 
suprasternal  notch  and  the  interclavicular  ligament.  (3)  Find  the  pronounced 
elevation  between  the  first  and  second  pieces  of  the  sternum.  This  is  the  manu- 
brio-gladiolar  joint,  and  is  the  point  concerned  in  the  rule  for  counting  the  ribs. 


]  .evator  costs  and 
accessor! us 


Scalenus  medius 


GROOVE  FOR  SUBCUWIAN 
ARTERY 


Scalenus  anticus 


GROOVE  FOR  SUBCLAVIAN 
VEIN 


SHAFT 


Levator  costae 
Accessorius 

(insertion) 
Cervicalis  ascendena 

(origin) 
Serratus  posticus 

superior 

(insertion) 

Scalenus  posticua 


Third  dictation  of 
serratus  maguua 


External 
intercostals 


FIG.   138.— FIRST  AND  SECOND  RIBS. 


Rule  :    this  ridge  corresponds  to  the  cartilage  of  the  second  rib.      (4)    Find   tl 
sterno-clavicular  articulation.      See  if  it  is  freely  movable,  as  it  should  be.      Not 
when   you   dissect  this  region  the  presence    of  an  interarticular  fibro-cartilae 
dividing  the  sy  no  vial  cavity  into  two  compartments — an  inner  and  an  outer. 
Note  that  seven  true  ribs  articulate  by  their  cartilages  with  the  sternum  ;  that 
except  that  of  the  first  rib  are    movable.      (6)   Examine   the   metasternum 
cnsiform    jinn-ess  to  see  its   deflection,   whether    lateral,  forward,   or  posterioi 
(7)  Count  the  ribs  and  study  the  nature  of  the  chondro-costal  articulation. 

198 


THE   THORAX. 


199 


Dissect  the  following  structures  and  study  them  carefully  : 

1.  The  subclavius  muscle  and  the  costo-clavicular  ligament. 

2.  The  external  intercostal  muscles  and  their  fasciae. 

3.  The  internal  intercostal  muscles  and  their  fasciae. 

4.  The  intercostal  fasciae,  internal,  middle,  and  external. 


An  interartieular 
ligament 


The  plate  of  flbro- 
cartilage  between 
manubrium  and 
meso -sternum 


SIXTH  RI3    H 


SEVENTH  RIB 


FIG.  139. — THE  STERNUM. 
(Left  side,  showing  ligaments  ;  right  side,  the  synovial  cavities/ 


5.  The  anterior  chondro-sternal  ligaments. 

6.  The  anterior  common  sternal  ligament  of  periosteal  derivation. 

7.  The  scalenus  anticus,  inserted  into  the  scalene  tubercle  of  the  first  rib. 

8.  The  scalenus  medius,  inserted  into  the  scalene  depression  of  the  first  rib. 

9.  The  subclavian  groove,  between  the  scaleni  muscles  on  the  first  rib. 
10.  The  groove  for  subclavian  vein  on  the  outer  surface  of  the  first  rib. 


200  PRACTICAL    ANATOMY. 

1 1.  The  relation  of  subclavian  artery  and  vein  on  first  rib. 

12.  A  digitation  of  serratus  magnus  muscle  on  the  first  rib. 

13.  Study  the  insertion  of  the  scalenus  posticus  muscle  on  the  outer  surface 
of  the  second  rib.     Also  the  digitations  for  the  serratus  magnus  muscle  on  the 
second. 

The  Subclavius  Muscle. — Dissection  of  this  muscle  requires  much  care. 
Cut  the  costo-clavicular  ligament  and  the  sterno-clavicular  ligaments  and  then 
lift  the  clavicle.  This  will  bring  the  muscle  into  view.  The  muscle  has  a  strong 
sheath.  Notice  that  the  space  between  this  muscle  and  the  pectoralis  minor  is 
bridged  by  the  clavi-pectoral  fascia.  (Fig.  132.)  Note  the  origin  of  the  sub- 
clavius  from  the  first  rib  at  the  junction  of  its  cartilage  ;  its  insertion  into  a  groove 


External 
intercoatala 


Internal 
intercostals 


External 
intercostals 


Internal 

intercostals 


Infra-costales 


FIG.  140. — THE  INTERCOSTAL  MUSCLES. 

on  the  under  surface  of  the  clavicle,  middle  two-fourths.  The  structures  you  will 
now  see  under  the  clavicle  are:  (i)  The  subclavius  muscle  and  its  sheath;  (2) 
the  subclavian  artery  and  vein  ;  (3)  the  brachial  plexus  of  nerves. 

The  scaleni  muscles  are  three  in  number — anticus,  medius,  and  posticus. 
A  few  movements  of  the  forceps  will  develop  their  insertions — two  into  the  first 
and  one  into  the  second  rib. 

The  intercostal  muscles  and  fasciae  occupy  the  intercostal  spaces.  The 
intercostal  spaces  are  eleven  on  each  side.  Kuch  space  is  occupied  by:  (i)  K\- 
ternal  and  internal  intercostal  muscles  ;  (2)  external,  middle,  and  internal  inter- 
costal fasciae  ;  (3)  intercostal  arteries,  veins,  and  nerves. 

The  external  intercostal  muscles  are  descending — /.  c.,  their  fibres  pass 


THE   THORAX.  201 

downward  and  inward,  toward  the  median  line  of  the  body.  (Fig.  140.)  They 
extend  from  the  tubercle  of  the  rib  behind  to  the  costo-chondral  joint  in  front. 

The  internal  intercostal  muscles  ascend  ;  their  fibres  pass  inward,  upward, 
and  toward  the  mid-line  of  the  body.  They  extend  from  the  sternum  in  front  to 
the  angle  of  the  rib  behind. 

The  osteology  of  the  ribs  must  be  reviewed.     A  typical  rib  has  : 

1.  A  head,  or  articular  vertebral  extremity. 

2.  A  neck,  or  constiction,  anterior  to  the  head,  extending  to  the  tubercle. 

3.  An  articular  tubercle,  articulating  with  the  transverse  process. 

4.  A  non-articidar  tubercle,  for  ligamentous  attachment. 

5.  A  sternal  extremity,  for  articulation  with  its  cartilage. 

6.  An  outer  surface,  covered  by  numerous  muscles. 

7.  An  inner  surface,  covered  by  pleura  mostly. 

8.  A  superior  border,  for  muscular  attachment. 

9.  An  inferior  border,  possessing  two  lips  and  a  subcostal  groove.     You  must 
become  familiar  with  all  these  points  on  the  dry  skeleton. 


POSTERIOR  KRAXClf  OF  LA  TF.RA  L 


ANTKKTOR  BRANCH  OF  LA  TKRAL 

<TTA.\i-:ors  xi-; 


THE  A  \TKKIOR  PRI- 
MARY DIVI«IO\ 
OF  AN  INTERCOS- 
TAL M-:ilVE 


THE  POSTERIOR    PR  I- 
MARY    IHVISI<>\    HI-' 
AN   INTERCOSTAL 
NERVE 

<:  \.\i:/,/o\  Oh'  I'osTKii- 
IOK  ROOT  OF  SPINAL 
M-:I;  \-K 

ANTERIOR  ROOT  OF 
XPIXAL  XEUVE 


.s  ) '.  V  r.  I  Til  /•;  Tl  ('  GANGLION  A  XI 
RA  .MI  ( 'OMM I  \\/( '.  I  .V  /'/•>• 

FIG.    141. — THE  INTERCOSTAL  NKKVF.S. 


LATERAL     CfTANE- 

or.v 


AN   INTERCOSTAL  SPACE 


An  external   intercostal 
*     muscle 

An  internal  intercostal 
muscle 


COSTO-CHONDRAL  JUNCTION 


Iiili'iiinl  iixiiuiiHtry 
artery 

TEHMISrS  0^  IXTKR- 
rox r.\i.   XKR\'K  LYIXI; 
OX  POSTERIOR  SUR- 
FM'K  (>/••  IXTKftl'OST.I  I, 
MI'SfLK.    A\l)   PASSIXH 
f\  FROXT    OF   THK    f\- 
TK  I!  XA  L     .WA  MM  A  R  Y 
ARTfJ/lY 


Figure  140  shows  the  mnscnli  infracostales.  These  muscles  arise  near  the 
angle  of  the  rib,  from  the  inner  surface  and  lower  border ;  they  are  inserted 
into  the  second  rib  above.  They  are  also  called  subcostals  or  mnsculi  subcostales. 

Intercostal  Fascia. — Remove  every  vestige  of  the  pectoralis  major,  and 
expose  the  intercostal  muscles.  Find  a  delicate  layer  of  fascia  covering  the  outer 
surface  of  the  external  intercostal  muscle.  This  is  the  external  intercostal  fascia. 
Trace  this  fascia  to  the  sternum.  You  can  now  see,  showing  through  this  fascia, 
the  internal  intercostal  muscle.  The  internal  intercostal  fascia  covers  the  inner 
surface  of  the  internal  intercostal  muscle.  The  middle  intercostal  fascia  is  be- 
tween the  two  intercostal  muscles. 

The  Intercostal  Nerves. — Figure  141  represents  the  cour'se  and  divisions 
and  relations  of  an  intercostal  nerve,  such  as  may  be  seen  in  the  second,  third, 
fourth,  fifth,  and  sixth  intercostal  spaces.  Students  frequently  graduate  unable 
to  locate  properly  an  intercostal  nerve.  You  are  to  note  the  following  stages  of 
an  intercostal  nerve  : 

1.  -The  nerve  is  formed  by  an  anterior  and  a  posterior  root. 

2.  The  posterior  or  sensory  root  has  a  ganglion. 

'4 


PRACTICAL  ANATOMY. 


4. 
5. 
6. 


3.  The  intercostal  nerve  lies  between  the  pleura  and  external  intercostal 
muscle. 

The  nerve  throws  off  muscular  branches. 

The  nerve  throws  off  lateral  cutaneous  branches. 

The  nerve  is  in  the  substance  of  the  internal  intercostal. 

7.  The  nerve  is  on  the  posterior  surface  of  the  internal  intercostal. 

8.  The  nerve  passes  in  front  of  the  internal  mammary  artery. 

9.  The  nerve  throws  off  anterior  cutaneous  branches. 

The  branches  of  the  intercostal  nerve  are  :  (i)  Muscular,  to  the  internal  and 
external  intercostals,  the  infracostales,  the  serratus  posticus  superior,  the  triangu- 
laris  sterni,  and  levatores  costarum  ;  (2)  cutaneous  branches,  lateral  and  anterior. 
Now  you  may  find  the  nerves  according  to  the  diagram.  You  will  find  the 


Sterno-hyoid 


Stern  o-thyroid 


Triangularia 
a  terui 


Transveraalis  abdominis 

FIG.   142. — THE  MUSCLES  ATTACHED  TO  THE  BACK  OK  THE  STERNTM. 


intercostal  arteries  with  the  nerves  to  some  extent.     In  this  dissection  care  must 
be  taken  not  to  injure  the  pleura. 

\\licrc  to  I'ind  tlic  Internal  Mammary  Artery  and  I'cins. — With  your  forceps 
go  through  the  soft  structures  one-half  of  an  inch  to  the  outer  margin  of  the 
sternum  on  either  side.  Try  to  find  this  artery,  and  ligate  the  same,  without 
injuring  the  pleura.  In  reaching  this  artery,  do  you  cut  through  the  external 
intercostal  muscle?  No.  Do  you  cut  through  the  three  intercostal  fascia.-  and 
internal  intercostal  muscle?  Yes.  Give  the  location  of  the  internal  mammary 
artery.  It  lies  between  the  pleura  and  internal  intercostal  fascia.  It  has  two 
companion  veins. 

The  Inner  Surface  of  the  Sternum  and  Ribs  (Fig.  142).    See  : 
i.   The  internal  intercostal  muscles,  eleven  pairs  on  each  side. 


77//1    THORAX. 


203 


» 


2.   The  origin  of  the  stcrno-liyoid  muscle. 
3  .   The  origin  of  tJie  sterno-tJiyroid  muscle. 

4.  The  origin  and  insertion  of  the  triangnlaris  stcrni. 

5.  The  costal  and  sternal  origins  of  t/te  diapJiragm. 

6.  The  parietal  layer  of  the  pleura,  through  which  you  can  see  the  muscles. 

7.  The   internal  mammary  artery  and  veins,  on  each  side   of  the  sternum, 
giving  off  their  anterior  intercostal  and  other  arteries.      (Fig.  143.)          8 

Dissection.  —  Cut  through  the  ribs  in  the  mid-axillary  line.      (Fig.  145.)     Cut 
through  the  abdominal  walls  along  the  margin  of  the  false  ribs.      Cut  through 


PHRENIC  NERVE 

Subclavian  artery 
Subclavian  vein,  cut 


Anterior  intercostal  branch 


Anterior  intercostal  branch 


Mnsculo-phrenic  artery 


Deep  circumflex  iliac  artery    - 


Common  carotid  artery 

Internal  jugular  vein 
Subclarian  rein,  cut 
Soaleuus  anticus  muscle 


Trianpcularis  aterni  muscle 
Perforating  branch 


Superior  epigastric  artery 


Deep  epigastric  artery 


FIG.   143. — SCHEME  OF  THE  INTKRNAI.  MAMMARY  ARTERY. 


the  diaphragm  close  to  the  ribs  and  sternum.  Then  elevate  from  below 
the  section  of  thoracic  wall  you  have  made  loose.  As  you  turn  this  section  up 
you  will  see  a  large  amount  of  anterior  mediastinal  connective  tissue  behind  the 
sternum.  Elevate  the  section  slowly  ;  let  an  assistant  divide  the  connective 
tissue,  and  do  not  injure  the  numerous  structures  that  enter  or  leave  the  apex 
of  the  thorax. 

Figure  141  shows  the  infracostales.  These  muscles  arise  near  the  angle  of 
the  ribs,  from  the  inner  surface  and  lower  border  ;  they  are  inserted  into  the 
second  rib  above.  They  are  also  called  snbcostals. 


204  PRACTICAL  ANATOMY. 

The  internal  mammary  artery  has  the  following  branches,  all  of  which  you 
can  easily  find  : 

1.  The  perforating  branches  that  come  through  the  five  or  six  upper  inter- 
costal spaces  and  supply  the  major  pectoral  muscle  and  the  mammary  gland. 

2.  The  mediastinal  branches  to  the  mediastinal  connective  tissue  and  glands 
under  the  sternum.      They  also  supply  the  thymus   gland  in  the  foetus  or  its 
remains  in  the  adult,  hence  they  are  called  also  tliyinic  'arteries. 

3.  The  sternal  branches,  quite  small  and  numerous,  to  the  sternum  and  tri- 
angularis  sterni  muscle. 

4.  Pericardiac  brandies  to  the  anterior  surface  of  the  pericardium. 

5.  The  comes  nervi  phrenici  is  a  long,  slender  artery  that  accompanies  the 
phrenic  nerve  to  the  diaphragm.     You  will  find  this  nerve  between  the  pleura 
and  pericardium. 

6.  The   anterior  intercostals  supply  the  six  upper  intercostal  spaces.     There 
are  two  in  each  space,  one  above  and  one  below.     They  anastomose  with  the 
posterior  intercostal  arteries  from  the  aorta. 

7.  The  musculo-phrenic,  that  furnishes  the  anterior  intercostal  arteries  to  the 
remaining  spaces.      It  also  supplies  branches  to  the  diaphragm. 

8.  The  superior  epigastric  passes  through  the  diaphragm  between  its  costal 
and  sternal  parts,  enters  the  sheath  of  the  rectus  muscle,  finally  the  muscle  itself, 
and  anastomoses  with  the  deep  epigastric  branch  of  the  external  iliac  artery. 

The  internal  mammary  artery  is  a  branch  of  the  subclavian,  as  you  saw  when 
you  dissected  the  neck.  Its  parietal  branches  are  to  the  anterior  walls  of  the 
thorax  what  the  parietal  branches  of  the  aorta  are  to  the  posterior  walls  of  the 
thorax.  Now  go  down  between  the  sixth  and  seventh  cartilages  and  find  where 
the  artery  divides  into  the  musculo-phrenic  and  superior  epigastric. 

The  thoracic  walls  are  supplied  with  blood,  then,  by  intercostal  arteries. 
These  arteries  come  :  (i)  From  the  aorta  ;'  (2)  from  the  internal  mammary  ;  (3) 
from  the  subclavian  ;  this  latter  furnishing  the  artery  to  the  superior  intercostal 
space.  The  blood  from  this  area  is  collected  and  delivered  as  follows  :  the  first 
or  superior  intercostal  vein  is  tributary  to  the  vertebral  vein  ;  the  others  to  the 
azygos  veins,  in  the  posterior  mediastinal  space,  to  be  presently  dissected. 

The  triangularis  sterni  muscle  arises  from  the  lateral  aspect  of  th( 
sternum,  and  is  inserted  into  the  cartilages  of  the  third,  fourth,  fifth,  and  sixtl 
ribs. 


INTERIOR   OF  THE  THORAX. 

Geometrically  the  thorax  possesses  : 

1.  An  apex,  through  which  pass  :  (i)  The  oesophagus  ;  (2)  the  trachea  ; 
common  carotid  artery  on  the  left,  and  the  innominate  artery  on  the  right  side  ; 
(4)  the  phrenic,  pneumogastric,  sympathetic,  and  recurrent  laryngeal  nerves  ;  (5) 
the  internal  jugular  and  subclavian  veins  ;  (6)  the  thoracic  duct  ;  (7)  the  sterno- 
hyoid  and  sterno-thyroid  muscles  ;  (8)  the  third  and  fourth  layers  of  deep  cervi 
cal  fascia  form  the  pericardium  and  invest  the  longus  colli   muscle    respectively  ; 
(9)  the  subclavian  artery  on  the  left  side. 

2.  A  base,  formed  by  the  diaphragm.     This  is  a  niusculo-aponeurotic  struc- 
ture, in  relation   with   the   pleurae   and   pericardium  above  and   below  with   the 
peritoneum.      It  transmits:  (i)  The  aorta;  (2)  the  ascending  vena  cava  ;   (3)  tin- 
(i-sophagus  and  pneumogastric  nerves;   (4)  the  superior  epigastric  branch  of  the 
internal  mammary  artery  ;  (5)  the  thoracic  duct  ;  (6)  the  communicating  branch 
from  the  lumbar  veins  to  the  a/ygos  veins. 


THE   TJIOK.IX. 


205 


3.  An  anterior  wall,  formed  by  the  sternum  and  cartilages  of  the   ribs,  with 
their  investing   soft  parts.      On  this  we  find  the  internal  mammary  arteries  and 
their  veins,  and  the  sterno-hyoid,  sterno-thyroid,  and  triangularis  stern i  muscles. 

4.  A  posterior  wall,  formed  by  the  thoracic  portion  of  the  vertebral  column 
and  the  ribs  outward  from  their   heads  to  the  angles,  with  their   investing  soft 
parts. 

5.  Two  lateral  walls,  formed  by  the  ribs  and  intercostal  spaces,  between  the 
angles  and  the  costo-chondral  articulations. 


Vena  cava  superior 


Arch  of  aorta 

Pulmonary  artery 

BRONCHUS 

/ 
Pulmonary  vein 


ENSIFORM  CARTILAGE 

IK;.   144. — ANTERIOR  VIEW  OK  THE  LUNGS:   PERICARDIUM.     (Modified  from  Bourgery.) 


The  inlet  or  apex  of  the  thorax  is  bounded  by  the  sternum,  first  rib,  and 
first  thoracic  vertebra.  The  diaphragm  is  attached  to,  or  rather  has  its  origin  from, 
the  sternum,  ribs,  hgamenta  arcuata  interna  and  externa.  There  are  twenty- 
four  ribs,  twenty-two  intercostal  spaces,  and  forty- four  intercostal  muscles. 

The  interior  of  the  thorax  consists  of: 

1.  A  pulmonary  portion,  a  compartment  containing  the  lungs. 

2.  A  mcdiastinal  portion,  or  non-lung-containing  compartment. 

The  pulmonary  portion  of  the  thoracic  cavity  contains  the  lungs.    The  inner 


206 


PR  A  CTICAL    ANA  TOM  \ '. 


surfaces  of  ribs  are  covered  by  the  pleura  costalis.  The  lung  is  invested  by 
pleura,  just  as  the  abdominal  organs  are  invested  by  peritoneum.  The  layer  of 
pleura  covering  the  lungs  is  called  visceral  layer,  or  pleura  pulmonalis.  The 
pleural  cavity  is  the  space  between  the  two  layers  of  pleura.  This  cavity 
contains  only  a  small  amount  of  serum  for  lubrication.  You  will  often  find 
adhesions  between  the  parietal  and  visceral  layers  of  the  pleura,  the  result  of 
inflammation.  Frequently  you  will  find  many  ounces  of  fluid,  the  result  of 
hypersecretion  :  this  condition  is  hydro-tfiora.v.  Occasionally  you  will  find  pus 
in  the  pleural  cavity  :  this  is  pyo-tJwrax.  You  may  find  foetid  gas  :  this  is  pneumo- 
tliorax;  or  pus  and  gas,  pyo-pneuino-tliorax. 


Pectoralia  major  muscle 
Pectoralis  minor  muaclj 

SUPERIOR  LOBE 


,  Serratus  magnua 
muscle 


MIDDLE  LOBE 


SECTION  OF  SEVENTH  RIB 


Diaphragm 

STERNUM 


ENSIFORM  CARTILAGE 


FIG.   145. — ANTERIOR  VIKW  OF  THK  THORAX  \YITII  CHKST  WALL  RKMOVKD,  SIIO\VIM; 
THK  LUNGS.      (Modified  from  Bourgery.), 


Cavities  of  tubercular  origin  are  often  found  in  the  lungs.     In  these  case 
notice  the  cavity,  while  an  assistant  inflates  the  lung.    A  large  percentage  of  the 
cases  you  see  in  the  dissecting-room  have  pulmonary  tuberculosis ;  some  have 
croupous  pneumonia  ;  others,  pulmonary  gangrene. 

AntJiracosis  is  carbuncular  disease  of  the  lung.  This  you  will  find  occasion- 
ally. Every  adult  lung  you  will  see  on  the  tables  will  be  literally  covered  by 
carbonaceous  spots.  This  pigmentation  is  undoubtedly  produced  by  impure  air  ; 
still,  you  fail  to  find  it  in  domestic  animals  at  the  stock-yards.  Possibly  if  these 
animals  lived  forty  years,  they  would  show  the  same  spots  on  their  lung 
surfaces  that  are  found  in  man's  lungs. 

The  apex  of  the  lung  extends  one  and  one-half  inches  above  the  first  rib.    The 


THE   THORAX.  207 

base  of  the  lung  rests  on  the  pulmonary  surface  of  the  diaphragm.  The  lung  has 
a  pleuritic  attachment  to  the  vertebral  column,  called  the  ligauicntum  latmn 
pulmonis. 

Anatomical  Root  of  the  Lung. — Like  the  root  of  the  liver,  the  root  of  the 
lung  transmits  structures  whereby  the  lung  carries  on — (i)  the  functional  activity  ; 
(2)  the  nutritive  activity  of  the  lung.  By  the  latter  the  lung  as  an  organ  lives  ; 
by  the  former  the  lung  as  an  organ  aerates  the  blood.  Pull  the  lung  carefully 
over  the  cut  margin  of  the  ribs  (Fig.  145)  and  you  will  see  the  root  structures. 

Inflate  the  lungs  and  study  the  lobes  and  fissures.  Introduce  a  one-half  inch 
rubber  tube  into  the  trachea  and  inflate  the  lungs.  You  will  then  see  a  space, 
corresponding  to  one-third  the  anterior  surface  of  the  heart,  that  is  not  covered 
by  the  lungs  when  they  are  inflated.  If  you  could  mark  on  the  chest-wall  the  size 
of  this  space,  that  would  give  you  the  area  of  precordial  dullness  on  percussion. 
As  you  inflate  the  lungs  you  notice  the  right  lung  has  three,  the  left  two,  lobes. 

The  root  structures  of  the  lungs  are  : 

1.  The  bronchial  tubes,  air-conveying  conduits. 

2.  The  bronchial  arteries,  nutritive  conduits  to  the  lungs. 

3.  The  pulmonary  artery,  bearing  blood  laden  with  CO2. 


PLEURA  PULMONIS 


PLEURAL   CAVITY 


PLEURA  COSTAUS 


FIG.  146. — INVAGINATION  OF  PLEURA. 

The  three  structures  produced  by  invagination  of  pleura  may  be  schematically  represented  as  the  above 
figure  shows.  I.  The  visceral  layer,  or  pars  pleurae  invaginata.  2.  The  parietal  layer,  or  pars  pleurse 
costalis.  3.  The  pleural  cavity.  The  same  schemejgives  like  results  in  accounting  for  the  cavity  and 
layers  in  connection  with  peritoneum  and  pericardium. 

4.  The  pulmonary  veins,  bearing  blood  -j-O,  and  — CO2. 

5.  The  pulmonary  sympathetic  nerves,  from  the  pulmonary  part  of  the  cardiac 
plexus. 

You  are  to  learn  that  the  thoracic,  abdominal,  and  pelvic  viscera  are  inner- 
vated' by  the  sympathetic  nerve.  '  The  cardiac  gangliated  plexus  supplies  the 
thoracic  organs  ;  the  solar,  the  abdominal  organs  ;  the  Jiypogastric,  the  pelvic 
organs.  Each  plexus,  however,  has  a  primary  element,  sympathetic,  and  a 
secondary  piieumogastric  element ;  hence  we  say,  in  general,  the  nerve-supply  is 
from  the  sympathetic.  Analytically,  we  speak  of  the  nerve-supply  as  sympa- 
thetic and  pneumogastric. 

The  Pulmonary  Trio. — The  sympathetic  nerve  always  accompanies  the 
artery  to  an  organ.  The  artery  that  nourishes  the  lungs  is  the  bronchial  ;  but 
this  artery  accompanies  the  bronchial  tube.  The  pulmonary  trio,  then,  consists 
of  the  bronchus,  the  bronchial  artery,  and  the  sympathetic  nerve-supply. 

Relation  of  bronchus,  artery,  and  veins  on  the  two  sides  are  as  follows  :  (i) 
On  the  right  side,  from  above  down — bronchus,  artery,  and  vein.  From  before 
back — vein,  artery,  bronchus. 

O»  the  left  side,  from  above  down — artery,  bronchus,  vein.  From  before 
back — vein,  artery,  bronchus. 


208  PRACTICAL  ANATOMY. 

What  is  the  relation  of  the  visceral  and  parietal  pleune  at  t/ie  roof  of  tlic  lung  f 
They  are  continuous,  since  the  pleura  is  an  invaginated  sac.      (Fig.  146.) 
Name  the  three  structures  produced  by  a  simple  invagination  of  the  pleura. 

1.  The  visceral  layer,  or  the  pars  pleurae  invaginata — pleura  pulmonis. 

2.  The  parietal  layer,  or  the  pars  pleura  costalis — parietal  pleura. 

3.  The  space  between  the  two  layers,  the  pleural  cavity. 
What  are  the  grand  divisions  of  the  parietal  pleura  f 

The  diaphragmatic,  the  mediastinal,  the  external  or  costal.  The  diaphrag- 
matic rest  on  the  diaphragm  ;  the  costal  on  the  ribs  and  internal  intercostal  mus- 
cles ;  the  mediastinal  is  in  relation  with  the  contents  of  the  mediastinum. 

Has  the  upper  extremity  of  the  pleura  pulmonis  any  important  relations  / 

Yes  ;  it  extends  an  inch  above  the  first  rib,  and  is  in  relation  to  the  sub- 
clavian  vessels,  which  lie  in  front  and  internal  to  the  apex  of  the  pleura. 

Is  there  any  special  provision  made  for  strengthening-  or  protecting  that  part  of 
the  dome  of  the  pleura  that  projects  abm>e  the  first  rib  ? 

Yes  ;  there  is  a  heavy  layer  of  subpleural  connective  tissue,  called  Sibson's 
fascia,  that  descends  from  the  scaleni  muscles  to  the  first  rib  and  gives  strength 
to  the  dome. 

HOIV  is  the  root  of  each  lung  secured  to  tJie  diaphragm  f 

By  a  fold  of  pleura  called  the  ligamentum  latum  pulmonis. 

Name  the  geometrical  parts  of  the  lung. 

The  apex,  base,  outer  surface,  inner  surface,  posterior  border,  anterior  border, 
and  pulmonary  root. 

What  is  the  inner  surface  of  the  lung  ? 

That  part  in  contact  with  the  mediastinum  and  pericardium  ;    it  is   concave. 

Where  is  the  base  of  the  lung  and  what  is  its  shape  f 

It  is  in  contact  with  the  diaphragm  ;  it  is  concave. 

What  can  you  say  about  the  anterior  border  of  the  lung  ? 

It  is  sharp  and  thin,  and  separates  the  external  from  the  inner  border.  The 
posterior  border  is  thick  and  round,  and  occupies  the  deep  groove  on  each  side 
of  the  vertebral  column. 

Is  there  any  provision  made  for  possible  physiological  increase  of  breathing- 
space  in  the  pleural  spaces  ? 

Yes  ;  the  same  principle  is  here  seen  as  is  observed  in  the  tortuous  arteries  of 
some  localities — a  condition  apparently  foreseen  to  meet  an  emergency.  The 
lung,  under  ordinary  conditions  of  man,  is  less  extensive  than  the  pleural  sacs. 
The  parietal  pleura  is  really  tortuous  in  the  region  of  the  anterior  border  of  the 
lung.  The  emergency  that  would  take  the  kinks  out  of  this  pleura  would  be 
physical  training,  where  wind  is  the  prime  desideratum,  as  in  pugilistic  mills. 
The  same  principle  is  seen  in  a  pregnant  uterus,  reducing  the  tortuosity  of  uter- 
ine arteries. 

THE  MEDIASTINAL  SPACES. 

1.  Anterior — Is  the  space  between  the  heart  and  sternum. 

2.  Middle — Is  the  space  occupied  by  the  heart  and  its  root  structures. 

3.  l\>stcrior — Is  the  space  behind  the  heart. 

The  Contents  of  the  Anterior  Mediastinal  Space  : 

1.  The  remains  of  tlic  thy  inns  gland — a  fu-tal  structure. 

2.  The  left  bracJno-ccplictlic  or  left  innominate  rein. 

3.  The  internal  mammary  artery  and  its  companion  veins. 

4.  The  nearly  obsolete  triangnlaris  sterni  muscle. 

5.  The  origin  of  the  sterno-hyoid  and  sterno-tltyroid  muscles. 

6.  The   large  amount  of  connective  /issue  you  noticed  when  you  opened  the 
thorax. 


/'///•:   THORAX. 


Contents  of  Middle  Mediastinal  Space  : 

I.   Pericardium  and  heart,  and  the  cardiac  root  structures. 
Phrenic  nerve  and  its  artery — ctrtcria  comes  ncrvi  phrenici. 
The  aorta,  pulmonary  artery,  and  pulmonary  vein. 
The  vena  cavce,  superior  and  inferior,  ascending  and  descending. 
The  trackeal  bifurcation  and  the  two  bronchial  tubes. 
Bronchial  lymphatic  glands  and  their  vessels  and  nerves. 
The  cardiac  plexus  of  the  sympathetic  nerve. 


HYOID  BONE 

Thyro-hyoid  membrane 

THYROID  CARTILAGE 


Sterno-thyroid  muscle 
Crico-thyroid 
membrane 

Crioo-thyroid  muscle 

THYROID  GLAND 

Right  common  earotid 

artfrii 

RIGHT  PNEUMO- 
GASTRIC  NERVE 

Ili'ihl  in/midl  jii'/idnr 
rein 

Level  of  sternum 

SECTION  OF  CLAVICLE 
SECTION  OF   FIRST  RIB 


SECTION  OF  STERNUM 


Thyro-hyoid  muscle 


Lateral  portion  erieo- 
thyroid  membrane 


Omo-hyoid  muscle 


7  Sterno-mastoid  muscle 


CRICOID  CARTILAGE 
FIRST  RING  OF  TRACHEA 


TRACHEA 

Left  suspensory 

ligament 
LEFT  RECURRENT 

NER  VJJ 

(Esophagus 

Left  innominate  vein 


LEFT  LOBE  OF  TIIYMUS 


Left  internal  mammary 
artery 


Pericardium 


SECTION  OF  FIFTH  RIB 
CARTILAGE 


ENSIFORM  CARTILAGE 


FIG.   147. — THYMUS  GLAND  IN  A  CHILD  AT  BIRTH. 


The  Posterior  Mediastinal  Contents : 

1.  The  aorta  and  posterior  intercostal  arteries. 

2.  The  oesophagus  and  pneumogastric  nerves. 

3.  The  vena  asygos  and  intercostal  veins. 

4.  The  thoracic  duct  and  its  fatty  bed. 

5 .  The  thoracic  .gangliated  sympathetic  cord. 

6.  The  greater,  lesser,  and  smallest  splanchnic  nerves. 


210  PRACTICAL    ANATOMY. 

7.  The  intercostal  nerves,  each  giving  off"  two  communicating  branches — ranii 
coinnmnicantes — to  the  ganglia  of  the  sympathetic  nerve  in  the  thorax. 

Dissection  of  these  regions  must  be  done  with  the  forceps.  No  cutting  instru- 
ment should  be  used.  Proceed  in  this  order:  (i)  Find  the  phrenic  nerve,  a 
branch  of  the  third  and  fourth  cervical,  and  the  arteria  comes  nervi  phrenici,  a 
branch  of  the  internal,  mammary  artery,  on  either  side  of  the  pericardium, 
between  this  structure  and  the  pleura.  This  nerve  comes  from  the  third  and  fourth 
cervical  plexus.  It  lies  on  the  scalenus  anticus  muscle  in  the  neck.  It  enters 
the  mediastinal  space  between  the  subclavian  artery  and  vein.  It  passes  anterior 
to  the  root  of  the  lung.  It  communicates  with  the  sympathetic,  with  the  nerve 


SUP*  v. c 


FORAMEN  OVALE 


PLAC  E  N  T  A 
Fu;.     148. — SCIIKMU    OK    THE    ]''<KTAI.    CIRCULATION. 

to  the  subclavius,  and  with   the  ansa  hypoglossal   loop.      It  is  distributed  to  the 
diaphragm,  pleura,  pericardium,  and  diaphragmatic  peritoneum. 

The  pericardium  has  :  (i)  A  base,  attached  to  the  diaphragm  ;  (2)  an  apex. 
continuous  above  with  the  third  layer  of  deep  cervical  fascia.  It  may  have 
much  fat.  It  has  a  visceral  layer,  a  parietal  layer,  and  a  cavity.  The  latter  is 
the  space  between  the  two  layers,  and  contains  a  small  quantity  of  fluid  for  lubri- 
cation. It  may  contain  many  ounces  of  fluid — this  is  hydro-pericardium.  Note 
the  relation  of  the  inflated  lung  to  the  pericardium  and  poststernal  connective 
tissue.  (Fig.  I  IO.)  Make  traction  on  the  diaphragm  where  the  pericardium  is 
attached,  and  observe  that  this  cannot  IK-  depressed  because  of  its  continuity  with 
the  third  layer  of  the  cervical  fascia.  Inflate  the  pericardiac  sac  ;  then  cut  the 
parietal  layer  of  the  pericardium. 


THE   THORAX.  211 

The  Thymus  Gland  or  Body. — You  will  find  the  fibrous  remains  of  this 
gland  on  the  anterior  part  of  the  pericardium  in  the  adult,  in  the  anterior  inedias- 
tinal  space.  This  gland  is  a  structure  of  foetal  life  ;  in  children  two  years  old  it  is 
quite  large.  (Fig.  147.)  In  the  four  months'  foetus  the  thymus  is  in  appearance 
like  the  lung,  on  casual  examination,  and  is  frequently  mistaken  for  this  organ 
by  the  novice. 

The  cardiac  root  structures  are  : 

1.  The  coronary,  or  nutrient,  artery  to  the  heart,  from  the  aorta. 

2.  The  voice  cavo?,  coming  from  the  whole  body  with  venous  blood. 

3.  The  pulmonary  arteries,  conveying  blood  to  the  lungs. 

4.  The  pulmonary  veins,  returning  blood  from  the  lungs. 

5.  The  aorta,  distributing  blood  to  the  whole  body. 

6.  The  cardiac  branches,  from  the  sympathetic  and  vagus  nerve. 

How  to  Study  Relations  of   These  Structures  Which  You  liavc  UOT.V  Exposed, 


SUPERIOR  LOBE  OF  RIGHT  LUNG 

Aorta 

Pulmonary  artery  • — • 
flIGHT  AURICULAS  APPENDIX 
MIDDLE  LOBE 


OUCTUS  ARTERIOSUS 


Pulmonary  artery 

SUPERIOR  LOBE  OF  LEFT 
LUNG 


„            .  LEFT  AURICULAR  APPENDIX 

~i j Pulmonary  artery 


INFERIOR  LOBE 
i—  Descending  aorta 


FIG.   149.— ANTERIOR  VIEW  OF  FCETAL  HEART,  VESSELS,  AND  LUNGS. 


Regardless  of  the  Particular  Arbitrary  Space  (Fig.  145). — (i)  Locate  in  the  mid- 
dle the  ascending  part  of  the  arch  of  the  aorta  (Fig.  153);  (2)  to  the  right  of  this 
is  the  descending  vena  cava  above  and  the  ascending  vena  cava  below  ;  (3)  to 
the  left  of  the  aorta  is  the  common  pulmonary  artery.  The  remaining  struc- 
tures are  the  pulmonary  veins,  which  may  be  seen  by  turning  the  apex  of  the 
heart  toward  the  right  sjioulder. 

Notice  now  particularly  the  pulmonary  artery  (Fig.  148),  for  it  is  the  one 
structure  in  this  root  that  complicates  relations.  At  its  origin  it  overlaps  the 
first  part  of  the  aorta  ;  separate  these  vessels — the  aorta  from  the  pulmonary 
artery.  Next  it  divides  into  a  right  pulmonary  and  a  left  pulmonary.  The  left 
pulmotiary  passes  to  the  left  lung,  in  front  of  the  descending  aorta  and  left 
bronchus.  The  right  pulmonary  artery  passes  to  the  right  lung,  behind  (i)  the 
aorta,  (2)  the  vena  cava,  (3)  the  phrenic  nerve  and  its  artery,  and  (4)  below  the 
right  bronchus. 

The  ductus  arteriosus  (Fig.  149)  in  the  foetus  is  a  vessel  connecting  the  pul- 


212 


PRACTICAL  ANATOMY. 


monary  artery  and  the  under  surface  of  the  arch  of  the  aorta  ;    in  the  adult  you 
must  find  here  in  this  place  the  fibrous  remains  of  this  foetal  structure. 

The  ascending  vena  cava  passes  through  the  caval  opening  in  the  dia- 
phragm. You  see  it  when  you  open  the  pericardium.  Its  length  is  about  one- 
half  of  an  inch,  above  the  diaphragm  in  the  pericardium. 


Right  common  carotid 

artery 

Right  internal  jugular 
vein 


RIGHT  LYMPHATIC  DUCT 

Innominate  artery 

RIGHT  PNEUMO- 

GASTRIC  NER  VE 

Right  innominate  vein 

Internal  mammary  vein 

Trunk  of  the  pericardiac 
and  t/iymic  veins 
Vena  cava  superior 


Vena  azygos  major 


Vena  azygos  minor,  cross- 
ing spine  to  enter  vena 
azygos  major 

Hepatic  veins 


Vena  cava  inferior 

Right  phrenic  artery 
Cveliac  axis 

Rig/it  middle  suprarenal 
artery 


Right  spermatic  artery 
Right  spermatic  vein 


Left  common  carotid 

artery 
LEFT  PXKC 

TRIC  SERVE 

THORACIC  DUCT 

Ly't  innoininnli  r-  in 

Left  subclavian  artery 


Left  superior  intercostal 
vein 

RECURKKXT 
LARYXGEAL 
XER  VE 


Vena  azygos  tertius 

(ESOPHAGUS 

Left  upper  azygos  vein 

(Esophageal  brnm-.'iex 
from  aorta 

Vena  azygos  minor 


THORACIC  DUCT 


Left  phrenic  artery 


Li'fl  iniild/i- 

artery 

RECEPTACULUM  CHYLI 


f!u/n-ri<ir  mi-s 
artery 

Left  ascetidini/  lumbar 

vein 
Left  spermatic  vessel* 


Inferior  mesenteric 
artery 


In..  150. --Tm    ARCH  OK  THE  AORTA,  THK  THORACIC  AORTA,  AND  THE  ABDOMINAL  AOHTA,  \\TIH 

THE    SUI'KRIOR    AND    iNhl.KIoK     V 1  N\    C\VA   AND   THK.    INNOMINATE   AND    AZYGOS    Vl-'.IN.s. 


The  descending  vena  cava  is  made  up  by  the  confluence  of  the  right  and 
left  brachio-cephalic  or  innominate  veins  ;  and  the  vena  azygos  major,  tin-  pen- 
cardiac,  thymic,  and  cesophageal  veins  are  its  subsequent  tributaries.  It  returns 
the  blood  to  the  right  auricle  of  the  heart  from  above  the  diaphragm. 

The   brachio-cephalics — right  and  left,  also  called  the  innominate  veins— 


THE   THORAX.  213 

are  formed  by  the  confluence  of  the  internal  jugular  veins  and  the  subclavian 
and  the  lymphatic  ducts.  (Fig.  150.) 

The  left  brachio-cephalic  vein  (Fig.  i  50)  is  the  one  structure  that  complicates 
relations  at  the  root  of  the  neck.  This  vein  lies  in  the  anterior  mediastinal 
space,  behind  the  first  piece  of  the  sternum.  Great  care  must  be  taken  not  to 
rupture  this  vessel  or  its  tributaries  when  you  remove  the  sternum  and  subse- 
quently dissect  this  region.  It  is  formed  by  the  confluence  of  the  left  internal 
jugular  vein,  the  thoracic  duct,  the  left  subclavian  vein,  the  left  superior  intercos- 
tal, and  the  inferior  thyroid  veins.  It  crosses  (i)  the  left  subclavian  artery  ;  (2) 
the  left  common  carotid  artery  ;  (3)  the  two  pneumogastric  nerves  and  the  left 
phrenic  nerve  ;  (4)  the  innominate  artery  ;  (5)  the  left  recurrent  laryngeal  nerve  ; 
(6)  the  trachea  ;  (7)  the  oesophagus. 

The  thoracic  duct  (Fig.  i  50)  in  many  cases  is  filled  with  blood,  the  valves 
at  its  terminus  not  being  able  to  resist  the  pressure,  used  in  embalming  the 
dissecting  material.  The  many  cases  reported  by  students  of  absence  of  this  ves- 
sel have  no  foundation  in  fact,  but  belong  to  a  host  of  finds  and  absences  which 
may  collectively  be  known  as  cases  of  first  dissection. 

Develop  now  the  origin  from  the  aorta  of  the  innominate,  the  left  common 
carotid,  and  left  subclavian  arteries.  You  have  dissected  the  branches  of  these 
structures  in  your  work  on  the  neck  ;  now  review  their  relations.  See  the  innom- 
inate artery  dividing  behind  the  right  sterno-clavicular  articulation  into  the  right 
common  carotid  and  right  subclavian  arteries. 

The  thoracic  part  of  the  aorta  has  two  divisions.  The  student  will  have 
noticed  that  this  structure  is  in  both  the  middle  and  posterior  mediastinal  spaces. 
You  must  remember  that  classification  of  structures  in  reference  to  specific 
regions  is  at  best  a  very  arbitrary  institution  ;  that  a  knowledge  of  anatomy  con- 
sists in  a  thorough  acquaintance  with  organs  wherever  found,  rather  than  in  an 
ability  to  recite  instanter  an  artificial,  arbitrary  classification  of  structures  found 
in  parte  in  a  given  region. 

1.  The    aortic   arch — three  propositions:    (i)  It  begins  at  second  sterno- 
chondral  articulation  on  the  right  side  ;    (2)  it  ends  at  the  fifth  thoracic  vertebra 
on-left  side  ;   (3)  its  branches  are  :  coronary,  innominate,  left  common  carotid,  left 
subclavian  arteries.  4 

2.  The  thoracic  aorta — three  propositions  :   (i)  It  begins  at  the  fifth  thoracic 
vertebra  on  left  side.    (2)  It  ends  at  the  twelfth  thoracic  in  the  mid-line.      (3)  Its 
branches  are  :  (i)  Pericardiac  to  the  pericardium  ;  (2)  cesophageal  to  the  oesopha- 
gus ;   (3)  bronchial  to  the  bronchi,  and  lung-substance  ;   (4)  the  posterior  medias- 
tinal branches,  to  the  glands   and  connective  tissue  ;  (5)  the  intercostals,  ten  in 
number,  to  the  muscles  and  fasciae  in  the  intercostal  spaces  and  to  the  skin  cov- 
ering these  structures. 

Practical  Dissection  Observations. — (i)  Note  that  the  branches  to  the  bronchi, 
oesophagus,  glands,  and  pericardium  are  given  off  from  the  anterior  part  of  the 
aorta,  or  some  derivative  of  the  same.  (2)  Note  that  the  mediastinal  glands,  in 
nearly  every  case,  contain  a  fluid  of  inky-black  color.  This  dark  color  is  pro- 
duced by  absorption  of  anthracite  particles.  When  enough  has  accumulated  to 
produce  carbuncnlar  disease  of  the  lung,  the  patient  has  anthracosis.  You  must 
make  this  practical  distinction  :  Every  lung  you  find  will  have  carbonaceous  pig- 
mentations ;  not  every  lung  will  have  enlarged,  inky-fluid-containing  lymphatics 
— only  some  will  show  this  condition.  Some  lungs  will  possess  carbuncular 
nodules  and  nodes  ;  these  always  have  enlarged  lymphatics,  filled  with  inky  fluid, 
if  the  disease  is  anthracosis. 

Conclusion. — In  every  adult  cadaver  you  will  see  pigmcnted  lungs.  In 
some  cadavers  you  may  see  anthracotic  lungs — that  is,  chronic  interstitial  pneu- 
monia, produced  by  inhalation  of  atmospheric  impurities,  the  basis  of  which  is 
carbon. 


2I4 


PR  A  CTICAL  ANA  TO  MY. 


A  Posterior  View  of  the  Thoracic  Viscera  (Fig.  151). — Turn  the  lung  still 
further  to  the  left  and  you  can  see  the  following  structures  even  without  cutting 
structures  as  shown  in  the  figure  :  ( i)  The  aorta  giving  off  its  intercostals  behind, 
and  its  visceral  branches  in  front ;  (2)  the  trachea,  left  bronchus,  oesophagus,  and 
thoracic  duct  behind  the  transverse  arch  of  the  aorta  ;  (3)  the  pulmonary  veins, 
right  and  left,  leading  to  the  left  auricle  of  the  heart ;  (4)  the  recurrent  laryngeal 
branch  of  the  left  pneumogastric  nerve  ;  (5)  the  trachea,  bifurcating  into  the  right 
and  left  bronchi,  opposite  the  fifth  thoracic  vertebra  ;  (6)  the  right  and  left  pneu- 


(ESOPHAGUS 
TRACHEA 

Innominate  artery 

RIGHT 
PNEUMOGA  STRIC 

NERVE 
Vena  cava  superior 

Intercostal  artery 


THORACIC  DUCT 

Left  subclavian  artery 

LEFT  PNEUMO- 
GASTRIC NER  VE 
LEFT  RECURRENT 
l.AR  YNGEA  L  NER  VE 

Intercostal  artery 

Pulmonary  artery 

BRONCHIAL  GLANDS 

Intercostal  artery 

LEFT  BRONCHUS 

/>/<  pulmonary  vein 

Descending  aorta 

LEFT  PLEURA 

Oblique  vein 

Left  coronary  artery 

Coronary  sinus 

Ijfft  marginal  branch  of 
left  coronary  artery 


Ventricular  branches  of 
coronary  artery 


Left  ventricle 


RIGHT  BRONCHUS 
Intercostal  artery 
Bronchial  artery 


POSTERIOR 
MONARY  /'/,/;.  \TX 

Hiijht  jmliiiunnry  in  ti'ry 
Right  pulmonary  vein 


—  Vena  azygos  major 

—  'RIGHT  PLEURA 

—  Lfft  auricle 


Posterior  cardiac  vein 


Posterior  intrrn  nt i  iftihir 
branch  of  right  coronary 
artery 


Fic;.  151.—  THK  HKART  AND  GKKAT  YKSSKI.S,  \VITII  TIIK  ROOT  01-  TIIK  I.UNC.S,  SKEN  KK<>M   1:1  IIIND 

(St.  Bartholomew's  Hospital  Museum.) 


mogastric  nerves  ;  (7)  the  pulmonary  sympathetic  plexus;  (8)  some  bronchial 
lymphatic  glands. 

The  Cardiac  and  Pulmonary  Plexuses.  —  (  )n  the  posterior  part  of  the. 
bronchi  you  will  find  some  nerves  ;  these  form  the  posterior  pulmonary  plexus. 
On  the  front  of  the  bronchi  you  will  also  find  some  nerves  ;  these  form  the  anterior 
pulmonary  plexus.  Now  cut  through  the  trachea  two  inches  above  its  bifurcation, 
and  you  will  sec,  immediately  in  front  of  the  bifurcation,  the  deep  eardiac  plexus. 
Look  under  the  arch  of  the  aorta  and  see  the  superficial  eardiae  plexus. 

The  above  plexuses  furnish  nerves  that  supply  the  heart  and  lungs.  The 
pulmonary  plexus  is  a  subdivision  of  the  cardiac  plexus.  The  terms  anterior  and 
posterior  pulmonary  are  used  for  convenience  in  describing  the  particular  regions 


THE    THORAX. 


215 


occupied  by  the  plexuses.     The  terms  superficial  and  deep  cardiac  are  used  for 
the  same  reason.     The  cardiac  plexus  is  formed  as  follows  : 

1.  By  cervical  and  thoracic  branches  of  the  pneumogastric  nerve. 

2.  By  branches  from  the  recurrent  laryngeal  nerve. 

3.  By  branches  from  the  cervical  sympathetic  nerve. 


to  G.ofRoot  ofPneunwy. 
tofetrosal  ff.o 
Glosso-ph, 


G.*GANGLION. 

Cardiac br.fkPneumogastnc     p.=  PLEXUS. 
andRtc.Larynyeal  Kcrvts        A.>  ARTERY. 

1.2.3.4.   BRAN  CHES. 
FROM    PNEUMOGASTHIC 

\  f  f-nr  •  i  NERVE  TOTHECAROIAC 

\G-ofWrisberg 


VuhantoS-PGanglicri 


+  r  so  *_•        LaraeS.Petrosal 

iff  u.  offnc  turwyajtric 

'   toffypoyloaaal  Jf. 

<r.  of  Ext.  CdroticLA. 


toPha.ryngea.1  P 
to  Inf.  Thyroid  A . 


Cardiac  Plexus 

.Coronary  Plexus 


tro-duadenal 


4th.. 

5^ 

from  Coayyoal 


5  Sup.Ifemorrhoidal . 
6  Spermatic  Plexus. 


Pelvic  P.  orlnfflypogastric. 

SUPPLIES  ALL  THE  PELVIC  VISCERA  AND  THE  PENIS. 


GangKon  Impar. 


Irsffi'tbtters  Compmd  of  Anatomy. 
FIG.   152. — THE  SYMPATHETIC  SYSTEM  OF  NERVES. 

Dissection  of  tlie  Posterior  Mediastinal  Space  (Fig.  150). — Remember,  you  are 
not  to  remove  the  heart  and  lungs  in  order  to  dissect  the  space.  Modus  oper- 
andi :  (i)  Turn  the  right  lung  to  the  left  side.  This  is  easily  done,  provided  there 
are  no  pleural  adhesions.  Where  adhesions  exist,  these  must  be  broken  up.  (2) 
Separate  the  parietal  pleura  from  the  ribs,  at  the  cut  margin  of  the  ribs,  and  you 


216  PRACTICAL  AN  ATOM  \. 

can  then  remove  it  from  its  parietal  attachment,  toward  the  mid-line  of  the  body, 
to  the  place  where  it  is  reflected  on  to  the  lungs,  just  as  easily  as  a  paper-hanger 
removes  his  paper  from  the  wall,  for  purposes  of  proper  adjustment,  before  his 
paste  becomes  set.  (3)  You  now  see  the  subpleural  connective  tissue — the 
medium  intervening  between  the  chest  walls  and  the  pleura. 

The  structures  now  seen  are  (Figs.  150  and  152):  The  fibres  of  the  inter- 
nal intercostal  muscles,  terminating  near  the  angle  of  the  ribs  posteriorly.  The 
space  between  this  pleura  and  the  vertebral  column  is  occupied  by  fatty  connec- 
tive tissue,  which  must  be  dissolved  in  gasolene,  ether,  or  benzine.  Now  you 
will  see,  as  in  figure  150,  the  intercostal  arteries,  veins,  and  nerves  lying  on  the 
external  intercostal  muscles.  You  soon  lose  sight  of  these  structures,  for  they 
pass  between  the  intercostal  muscles. 

The  thoracic  gangliated  cord  of  the  sympathetic  nerve  (Fig.  152)  is  easily 
dissected,  but  requires  a  delicate  touch  to  preserve  its  integrity,  such  is  the  deli- 
cacy of  its  structure.  You  can  find  a  ganglion  opposite  the  head  of  each  rib. 
Trace  two  little  branches  from  this  ganglion  to  the  spinal  nerve  ;  these  branches 
are  the  rami  communicantes. 

Figure  151  shows  the  spinal  nerves  near  their  exit  from  the  intervertebral 
foramina,  giving  communicating  branches — rami  communicantes — to  the  ganglia 
of  the  thoracic  sympathetic  cord.  It  also  shows  the  manner  in  which  the  si.v 
upper  distribute  their  branches  to  the  thorax,  and  the  six  Icnver  their  branches  to 
the  abdomen  by  the  splanchnic  nerves. 

Branches  of  the  Thoracic  Gangliated  Cord  (Fig.  152). — (i)  To  the  spinal 
nerves — rami  communicantes  ;  (2)  branches  connecting  the  ganglia ;  (3)  branches 
of  distribution.  Notice  the  six  upper  ganglia  give  off  branches  to  the  aorta  and 
its  branches  in  the  thorax,  to  the  bodies  of  the  vertebrae  and  their  ligaments,  and 
to  the  pulmonary  and  cardiac  plexuses.  Notice  the  six  lower  give  off  branches, 
(i)  to  the  aorta  and  its  thoracic  branches,  (2)  and  unite  to  form  the  splanchnic. 

The  splanchnics  are  the  great  abdominal  visceral  branches  from  the  thor- 
acic part  of  the  gangliated  cord  ;  they  are  named — 

1.  The  greater  splanchnic  nerve  (sixth,  seventh,  eighth,  and  ninth). 

2.  The  lesser  splanchnic  nerve  (tenth  and  eleventh). 

3.  The  smallest  or  renal  splanchnic  nerve  (twelfth). 
Can  these  nerves  be  seen  f 

Yes,  easily.  The  scheme,  as  set  forth  in  figure  152,  can.be  verified  by  any 
student  on  any  cadaver,  with  the  proper  care.  Note  that  the  three  splanchnic 
nerves  pass  through  the  diaphragm.  When  we  study  the  thoracic  aorta  we  will 
see  what  becomes  of  the  branches  of  distribution  from  the  upper  six  thoracic 
ganglia  ;  we  must  ask,  Why  are  they  so  small,  when  the  six  lower  are  so  large? 

The  vena  azygos   major  lies  on  the  vertebral  column.     (Fig.  150.)     It  i 
composed  of  the  intercostal  veins  from  the  thoracic  walls.      The  blood  from  th 
intercostal  spaces  of  the  left  side  is  collected  by  the  vena  azygos  minor.    Some 
times  two  small  azygos  veins  will  be  found  on  the  lett  side.      The  minor  is  tribu- 
tary to  the  major  azygos  vein.      Remember,  the  lett  superior  intercostal  vein  i> 
tributary  to  the  left  brachio-cephalic  ;  the  right  to  the  vertebral  vein. 

'The  thoracic  duct  lies  in  a  bed  of  fatty  connective  tissue,  between  the  aorta 
and  the  vena  a/ygos  major,  on  the  vertebral  column.  It  is  confluent  to  the  left 
brachio-cephalic  vein.  It  originates  in  the  receptaculum  chyli,  on  the  second 
lumbar  vertebra.  It  passes  through  the  aortic  opening  in  the  diaphragm.  This 
is  easily  inflated,  in  the  recently-dead,  before  the  material  lias  been  embalmed. 
To  do  this  inflation,  cut  into  the  brachio-cephalic  and  find  the  orifice  of  the  duct. 

The  oesophagus  extends  from  the  pharynx  to  the  stomach.  It  leaves  the 
thorax  |>y  the  o-sophagcal  opening  in  the  diaphragm.  Find  it  passing  behind 
(i)  the  arch  of  tin-  aorta,  (2)  the  trachea,  (3)  the  left  bronchus.  (4)  the  left  com 


: 


THE   THORAX. 


217 


mon  carotid  and  left  subclavian  veins,  and  (5)  pericardium.  Find  (6)  the  vena 
azygos  major  to  the  right,  and  (7)  the  aorta  to  the  left.  On  each  side  find  (8) 
the  pneumogastric  nerves.  Near  the  diaphragm  find  (9)  the  left  pneumogastric 
in  front,  (10)  the  right  behind  the  oesophagus — a  result  of  rotation  of  the  stomach. 
The  pneumogastric  nerves  (Fig.  153)  have  been  thoroughly  considered  in 
the  dissection  of  the  neck.  Still,  there  are  some  practical  relations  of  this  nerve 


RIGHT  RECUR- 
RENT LARYN- 
GEAL NERVE 

Transverse  cervical 

artery 
Right  common  carotid 

artery 
Suprascapular  artery 

Internal  jugular  vein 

PNEUMO  GA  STRIC 
NERVE 

Subclavian  vein 

Inferior  thyroid  vein 
PHRENIC  NER  VE 
Left  innominate  vein 
Ascending  aorta  -J-^ 

|r 

Superior  vena  cava 
RIGHT  BRONCHUS 

Branch  to  superior  lube 

of  lung 

Upper  branch  of  right 

pulmonary  urti'ri/ 

Branch  to  middle  lobe 

of  lung 
Right  pulmonary  vein 

RIGHT  AURICLE 

Right  coronary  artery 
Lower  branch,  of  right 
pulmonary  atii'ri/ 
THORACIC  VERTEBRA 

Intercostal  vein 

Intercostal  artery 

Vena  azygos  major 

Intercostal  vein 
Intercostal  artery  __ 

Intercostal  vein 
Intercostal  artery 


THYROID  BODY 
LEFT  RECURRENT 
LARYNGEAL 
NER  VE 
PNE  UMO  GA  S  TRIC 

NERVE 
Left  internal  jugular 

vein 
Left  common  carotid 

artery 
Left  subclarian  artery 

Left  subclavian  vein 

TRACHEA 

Inferior  thyroid  vein 

PHRENIC  NER  VE 

(hooked  aside) 
RECURRENT 
LARYNGEAL 
NERVE 
PNEUMOGASTRIC 

NER  VE 
DUCTUS  ARTERIOSUS 

Left  pulmonary  artery 


Pulmonary  artery 

Right  pulmonary 
artery 

LEFT  BRONCHUS 

Left  coronary  artery 

Upper  left  pulmonary 

.  vein 
RIGHT  VENTRICLE 

(Conus  arteriosiis) 
Lower  left  pulmonary 

artery 
Lvuier  left  pulmonary 

vein 

CESOPHAGUS 
(hooked  aside) 


THORACIC  DUCT 
Thoracic  aorta, 


FIG.  153. — THE  ARCH  OF  THE  AORTA,  WITH  THE  PULMONARY  ARTERY  AND  CHIEF  BRANCHES  OF 

THE  AORTA. 
(From  a  dissection  in  St.  Bartholomew's  Hospital  Museum.) 


in  the  thorax  I  wish  the  student  to  understand.  The  pneumogastric  nerve 
leaves  the  cranium  by  the  jugular  foramen.  You  found  it  in  the  carotid  sheath, 
between  the  internal  jugular  vein  and  common  carotid  artery  in  the  neck.  The 
two  pneumogastric  nerves  differ  in  their  relations  somewhat,  hence  dissect  them 
separately.  The  right  nerve  (Fig.  15 3)  crosses  the  right  subclavian  artery,  and 
at  once  gives  off  its  recurrent  or  inferior  laryngeal  nerve,  which  passes  upward 
and  inward,  behind  the  subclavian  and  common  carotid  arteries,  to  the  larynx, 
15 


2i8  PRACTICAL  ANATOMY. 

lying,  in  its  course,  between  the  oesophagus  and  trachea,  in  a  bed  of  fatty  connec- 
tive tissue.  In  the  lower  part  of  the  neck,  cervical  and  thoracic  cardiac  branches 
are  given  off  to  the  cardiac  plexus.  A  little  lower  are  given  off  pulmonary 
branches,  called,  from  their  distribution,  anterior  and  posterior  ;  these  supply  the 
lungs  through  the  pulmonary  gangliated  plexus.  CEsophageal  branches  from 
the  pneumogastric  form  the  plexus  gulae.  The  pneumogastric  nerve  leaves  the 
thorax  by  the  oesophageal  opening  in  the  diaphragm,  and  sends  branches  to  the 
solar  plexus,  from  which,  possibly,  all  the  abdominal  organs  receive  pneumogas- 
tric influence.  This,  however,  is  purely  physiological  speculation. 

On  the  left  side,  the  pneumogastric  nerve  passes  behind  the  left  brachio- 
cephalic  vein  and  in  front  of  the  arch  of  the  aorta.  As  it  is  crossing  the  arch  it 
gives  off  its  recurrent  laryngeal  branch.  This  nerve  passes  to  the  outer  side  of 
the  ductus  arteriosus  and  gains  the  side  of  the  left  bronchus  and  trachea.  The 
inferior  or  recurrent  laryngeal  nerves  supply  branches  to  the  trachea,  oesophagus, 
and  to  all  the  intrinsic  muscles  of  the  larynx  except  the  crico-thyroid  muscle. 

The  coronary  arteries  supply  the  heart.  They  are  given  off  from  the  ascend- 
ing aorta.  They  embrace  at  their  origin  the  common  pulmonary  artery  by  their 
divergence.  (Fig.  153.)  Blood  is  returned  from  the  heart  by  two  sources  :  (i) 
By  minute  veins  which  end  in  the  foramina  of  Thebesius  in  the  right  auricle  of  the 
heart.  (2)  Numerous  veins  come  together  to  form  the  great  coronary  sinus. 
This  sinus  opens  into  the  right  auricle  of  the  heart,  between  the  auriculo- 
ventricular  opening  and  the  ascending  vena  cava.  You  will  demonstrate  this 
opening,  and  also  the  valve,  called  the  coronary,  on  your  dissection. 

The  Right  Auricle  of  the  Heart. — Cut  through  the  wall  of  the  auricle  from 
the  ascending  to  the  descending  vena  cava  in  a  direction  from  above  downward. 
Now,  having  thoroughly  washed  the  parts,  you  will  see  :  (i)  The  appendix  auri- 
cula, and  (2)  the  atrium,  sinus,  or  principal  cavity  of  the  auricle.  In  the  atrium 
see  and  locate:  (i)  The  fossa  waits,  surrounded  by  a  rim  called  the  annnlns 
ovalis;  (3)  the  caval  and  auriculo-ventricular  openings  (Fig.  154);  (4)  the  coro- 
nary valve  or  valve  of  Thebesius  and  the  RustacJiian  valves, -at  the  respective 
openings  for  the  coronary  sinus  and  ascending  vena  cava  ;  (5)  the  musculi  pec- 
tinati,  which  you  will  see  on  cutting  through  the  appendix  auriculae.  These  latter 
are  mechanical  devices  for  giving  strength  to  the  walls  of  the  auricle,  analogous 
to  the  chordae  tendineae  in  the  ventricles. 

The  Semilunar  Valves  (Fig.  154). — Cut  into  the  aorta  and  pulmonary 
artery  an  inch  above  where  they  leave  the  heart,  and  demonstrate  these  valves. 
Fill  the  vessels  with  water  and  show  the  action  of  these  valves  in  preventing 
regurgitation.  In  the  central  point  of  each  free  margin  of  the  valve  find  the 
corpus  Arantius.  This  is  a  mechanical  device,  whereby  the  valves  occlude  more 
perfectly.  Also  find  in  the  aorta  the  sinuses  of  Valsalva,  or  aortic  sinuses,  oppo- 
site to  which  are  found  the  attached  margins  of  the  valves.  Above  the  fret 
margin  of  the  valves  find  the  coronary  arteries,  left  and  right,  given  off  from  tin 
aorta. 

The  auriculo-ventricular  valves,  right  and  left,  guard  the  respective  open- 
ings between  the  auricles  and  ventricles.  Cut  into  the  right  ventricle  (Fig.  i  54) 
and  study  the  mechanical  devices  known  as  columnar  carneae  and  chorda  ten- 
dineae ;  also  the  left  ventricle  study  in  the  same  manner. 

The  septa  are  :    (i)  The  interauricular.      In  this  you  see  the  fossa  ovalis.     In 
the  foetus  this  was  a  communication  between  the  auricles,  called  the  forumei 
ovale.      It  is  in  the  posterior  wall  of  the  right  auricle.      (2)  The  interventricular, 
separating  the  ventricles. 

Steps  in  Adult  Circulation. — ( i )  Blood  is  taken  from  below  the  diaphragm 
by  the  inferior  vena  cava,  and  from  above  the  diaphragm  by  the  descending 
\vna  cava,  to  the  right  auricle  of  the  heart.  (2)  Blood  flows  from  the  right 


s 

•• 


• 


THE  THORAX. 


219 


auricle*  through  the  auriculo-ventricular  opening,  to  the  right  ventricle.  This 
opening  is  guarded  by  the  right  auriculo-ventricular  valves.  (3)  Blood  flows 
from  the  right  ventricle,  by  the  pulmonary  artery,  to  the  lungs.  This  artery  is 
guarded  by  the  pulmonary  semilunar  valves.  (4)  Blood  flows  from  the  lungs  to 
the  left  auricle  of  the  heart  by  the  pulmonary  veins.  These  veins  have  no  valves. 
(5)  Blood  passes  from  the  left  auricle,  by  the  left  auriculo-ventricular  opening, 


Left  carotid 
Innominate 


Left  subclavian 


Right  pulmonary  artery 
Duclus  arteriosus 

Left  pulmonary  artery 

Pulmonary  artery 
Pulmonary  semilunar  valves 

LEFT  AURICULAR  APPENDIX 

Small  papillary  muscle  connected 
with  septum 

(1)  Columna  caruea 

CHORD/E  TENDINE* 


Anterior  papillary 
muscle 


Left  coronary  artery 


Vena  cava  inferior 
ANTERIOR  SEGMENT  OF  TRICUSPID  VALVE 

RIGHT  SEGMENT  OF  TRICUSPID  VALVE 

SECTION  OF  VENTRICULAR  WALL 

Vena  cava  inferior . 

lary  muscle 

FIG.  154.— ANTERIOR  VIEW  OF  THE  RIGHT  CHAMBERS  OF  THE  HEART,  WITH  THE  GREAT  VESSELS. 


(3)  Posterior  papil-    (2)  Columna  oarnea 
ile 


to  the  left  ventricle.  This  opening  is  guarded  by  the  left  auriculo-ventricular 
valves.  (6)  Blood  passes  from  the  left  ventricle  through  the  aorta  to  all  vascu- 
lar parts  of  the  body.  The  aorta  is  guarded  by  the  aortic  semilunar  valves. 
Systole  is  a  term  by  which  contraction  of  the  auricles  and  ventricles  is  desig- 
nated ;  diastole  is  its  opposite.  The  one  extrudes,  the  other  draws  in,  blood. 

The  Foetal  Circulation. — The  lungs  are  essentially  organs  whose  use   in 
distributing  the  blood  for  purification   begins  after  birth.      Before  the  product  of 


220  PRACTICAL    ANATOMY. 

conception  reaches  the  ninth  month  of  utero-gestation,  its  blood  is  distributed 
for  purification  in  an  organ  called  the  placenta.  This  placenta,  while  structur- 
ally very  different  from  the  lungs,  accomplishes  for  the  blood  of  the  foetus  just 


Right  innominate  vein 

Vena  cava  superior 
Right  pulmonary  artei~y 


Vena  cava  inferior 


Left  branch  of  portal  vein 

DUCTUS  VENOSUS 


Umbilical  vein 

Portal  vein 

Right  bnnifh  <>f 
portal  vein 


Umbilical  vein 


Umbilical  arteries  _ 1 


Hypogaitric  artery 


Left  innominti/p 
vein 


Arch  of  aorta 

DUCTUS  ARTERIOSUS 

Left  pulmonary 
artery 


Descending  aorta 


Superior 
mesenteric  artery 


Inferior 
mesenteric  artery 


Left  common  iliac 
artery 


I nt f rnnl  i/iui-  uri, 

Kill-null  /linear/ fry 


;.  155. — THK  HKART,  WITH  TIIK  ARCH  <>i    THK  AORTA,  TIIK  I'ILMONAKY  AKTK.KY,   1111     I- 

Al;  I  I  KloSUS,   AND   THE   VESSELS   CONCERNED    IN    TIIK    Fd'.TAI.   CIRCULATION. 
(From  a  preparation  of  a  foetus  in  the  Museum  of  St.  Bartholomew's  Hospital.) 


the  same  results  as  are  accomplished  by  the  lungs  /vW  part  cm.  The  purification 
of  the  blood  in  cither  case  is  in  accordance  with  the  law  of  physics  regulating 
the  diffusion  of  gases.  Blood,  on  entering  lung  or  placenta,  is  laden  with  O  )._,  ; 


THE  THORAX.  221 

on  leaving  the  same  it  is  laden  with  O.  The  difference,  then,  between  the  ante 
partem  and  post  partem  purification  of  blood  is  not  a  physiological  one  ;  but  a 
difference  is  to  be  found  in  certain  anatomical  routes  taken  by  this  blood,  in  the 
one  case  to  and  from  the  placenta,  in  the  other  case  to  and  from  the  lungs.  A 
study  of  the  metamorphosis  of  parts  after  functional  activity  ceases  is  replete 
with  interest,  since  it  shows  the  converse  of  the  law  of  physiology  that  growth 
is  the  correlation  of  function.  Study  the  following  steps  in  the  foetal  circulation, 
in  order  that  in  your  dissection  you  may  be  able  to  appreciate  the  several  fcetal 
vestiges  you  shall  find  there. 

1.  In  the  foetus  the  blood  is  purified  in  the  placenta  of  the  mother.      (Fig. 
155.)      It  is  taken  to  that  organ  by  the   hypogastric  arteries,  from  the  internal 
iliac  arteries. 

2.  It  is  returned  from  the  placenta  by  the  umbilical  vein,  as  follows  :  (i)  To 
the  ascending  vena  cava  by  the  ductus  venosus  ;  (2)  to  the  portal  vein  to  traverse 
the  liver,  and  finally  reach  the  ascending  vena  cava  by  the  hepatic  veins. 

3.  The  blood  from  above  the  diaphragm  reaches  the  heart  by  the  descending 
vena  cava,  as  in  the  adult. 

4.  The  blood  from  the  descending  vena  cava  passes  through  the  auricle  to 
the  ventricle,  and  thence  out  through  the  pulmonary  artery  ;  the  lungs  not  being 
yet  fitted  for  purifying,  the  blood  is  taken  by  the  ductus  arteriosus  to  the  aorta. 

5.  The  blood  from  the  ascending  vena  cava  passes  through  the  foramen  ovale 
(Fig.  154)  to  the  left  auricle,  thence  to  the  left  ventricle,  and  out  by  the  aorta. 

The  circulatory  apparatus  of  the  fcetus  possesses  : 

1.  The  umbilical  vein  brings  blood  from  the  placenta. 

2.  The  hypogastric  arteries  conveys  blood  to  the  placenta. 

3.  The  ductus  venosus  takes  blood  to  the  vena  cava. 

4.  The  ductus  arteriosus  connects  the  pulmonary  artery  and  aorta. 

5.  The  foramen  ovale  is  an   opening   between   the   auricles.      All   of  these 
structures  forming  the  circulatory  apparatus  of  the  fcetus  are  set  aside  at  birth, 
when  the  lungs  become  the  aerating  organ  for  the  blood.     By  non-use  these 
structures  lose  their  specific  characters — they  become  obsolete.     They  obtain  in 
the  adult  as  : 

1.  Remains  of  the  umbilical  vein,  the  round  ligament  of  the  liver. 

2.  Remans  of  the  hypogastric  arteries  near  the  urachus. 

3.  Remains  of  the  ductus  venosus  on  under  surface  of  liver. 

4.  Remains  of  the  ductus  arteriosus  between  aorta  and  pulmonary  artery. 

5.  Remains  of  the  foramen  ovale  in  posterior  wall  of  auricle. 

What  is  a  fcetal  vestige?  The  fibrous  remains  in  the  adult  of  an  organ  that 
under  the  conditions  of  the  fcetus  in  utero  was  a  necessary  organ  or  part.  The 
umbilicus  and  urachus  are  foetal  vestiges. 


What  are  the  grand  divisions  of  the  thorax  / 

The  thorax  may  be  subdivided  into  a  pulmonary  part,  occupied  by  the  lungs, 
and  a  mediastinal  part,  not  occupied  by  the  lungs. 

Is  the  word  thorax  synonymous  with  trunk  / 

No  ;  thorax  is  the  cavity  above  the  diaphragm  ;  trunk  means  the  whole  body 
except  the  head,  neck,  and  extremities. 

Explain  the  superior  mediastinal  space. 

This  is  a  space  bounded  above  by  the  superior  aperture  of  the  thorax  ;  below 
by  a  plane  limited  in  front  by  the  manubrio-gladiolar  articulation  and  behind  by 
the  body  of  the  fourth  thoracic  vertebra  ;  in  front  by  the  manubrium  ;  behind  by 
the  four  upper  thoracic  vertebme  ;  laterally  by  the  pleural  sacs.  This  space 


222 


PRACTICAL    ANATOMY. 


contains  the  following  structures,  which  you  may  find  on  your  work  :  (i)  The 
thoracic  portion  of  the  trachea ;  (2)  the  thoracic  portion  of  the  oesophagus  ; 
(3)  the  thoracic  portion  of  the  thoracic  duct ;  (4)  the  transverse  part  of  the 
aortic  arch  ;  (5)  the  imal  and  innominate  arteries  ;  (6)  the  thoracic  portion  of  the 
left  subclavian  artery  ;  (7)  the  innominate  veins,  and  the  superior  vena  cava  ;  (8) 
the  terminations  of  the  internal  mammary  veins  ;  (9)  the  terminations  of  the  inferior 
thyroid  veins  ;  (10)  the  superior  intercostal  vein  of  the  left  side  ;  (i  i)  the  two 
pneumogastric  or  vagi  nerves;  (12)  the  two  phrenic  and  cardiac  nerves; 
(13)  the  left  recurrent  or  inferior  laryngeal  nerve;  (14)  thymus  gland  in  the 
foetus  and  remains  of  the  thymus  in  the  adult. 

Describe  tJie  pericardium. 

It   is   a   fibro-serous   sac   surrounding  the   heart.      The  pericardium  is  cone- 


Innominate 


Right  pulmonary  vein 


RIGHT  AURICLE 
RIGHT  AURICLE  APPENDIX 

Right  coronary 

Branch  to  anterior  wall 
of  right  ventricle  ( pre- 
ventricular) 

Right  marginal  artery 
and  vein  (vein  of  Galen) 


Lfft  carotid 
Left  subclavian 


Left  pulmonary  vein 


LEFT  AURICULAR  APPENDIX 


Left  marginal  artery 


Anterior  intervenlriciilar 
branch  of  the  great  car- 
diac vein 


Left  coronary  (interven- 
tricular) 


Commencing  ra<li<-lf.i  nf 
posterior  intern-  iitrin- 
ular  vein 


FIG.  156.  —  ANTERIOR  VIEW  OK  THE  HEART,  SHOWING  ITS  ARTERIES  AND  VEINS. 


shaped,  the  base  being  attached  to  the  central  tendon  of  the  diaphragm,  tin 
apex  being  lost  in  the  fibrous  sheath  of  the  vessels  that  arise  from  the  base  o 
the  heart.  Structurally  the  pericardium  is  inelastic.  Above  it  is  continuous 
with  the  third  layer  of  deep  cervical  fascia.  The  pericardium  is  attached  in  front 
to  the  sternum  by  sterno-pericardial  bands. 

/•'roi/i  i^'liat  so/tree  <loes  the  pericardium  receive  its  blood-supply  / 

From   the  phrenic  below;  from  the  internal   mammary  in  front;  from  tin 
oesophagi  -al,  prricardiac,  and  bronchial  branches  of  the  thoracic  aorta  behind. 

From  u'liat  source  <jocs  (lie  pericardium  receive  its  nerve-supply  / 

From  the  phrenic,  vagus,  and  sympathetic. 

Xame   the  structures  at  the  base  of  (lie  heart  that  derive  Strengthening  bands 
from  the  pericardium. 


THE  THORAX. 


223 


The  aorta,  the  pulmonary  arteries  and  veins,  the  ductus  arteriosus. 

What  can  yon  say  of  the  investment  of  the  aorta  and  pulmonary  artery? 

They  are  invested  by  a  common  sheath  ;  behind  these  vessels  is  a  passage 
called  the  great  sinus  of  the  pericardium. 

Name  the  valves  of  the  heart  and  the  valves  of  its  vessels,  and  tell  hoiv  they  are 
formed. 

The  coronary,  the  Eustachian,  the  aortic  and  pulmonary  semilunar,  the  right 
and  left  auriculo-ventricular.  They  are  formed  by  folds  of  endocardium  and 
subserous  connective  tissue. 

What  are  the  grand  divisions  of  the  right  auricle  / 

The  auricular  appendix  and  sinus  venosus,  or  atrium.  This  auricle  forms  the 
front  part  of  the  base  of  the  heart.  Into  the  atrium  the  following  structures 


Right  carotid  artery 


Left  carotid  artery 
Left  subclavian  artery 

Aorta 
Ductus  arteriosus 

Pulmonary  artery 

Left  pulmonary  veins 

LEFT  AURICLE 

Left  coronary  artery 

Left  marginal  artery 

Oblique  vein  of  Marshall 

Left  marginal  vein 

PERICARDIUM 

Coronary  sinus 

erior  cardiac  vein 


Poster 


Innominate  artery 


\ena  cava  superior 

Right  pulmonary  veins 
RIGHT  AURICLE 

Vena  cava  inferior 

Right  coronary  artery 
Posterior  intervenlricular  vein 


Posterior  interventricular  branch 
of  right  coronary 


Anterior  interventricular 
branch  of  left  coronary 

FIG.   157. — POSTERIOR  VIEW  OF  THE  HEART,  SHOWING  ITS  ARTERIES  AND  VEINS. 

open:  (i)  The  descending  vena  cava;  (2)  the  ascending  vena  cava;  (3)  the 
auriculo-ventricular  opening ;  (4)  the  coronary  sinus ;  (5)  the  foramina  of 
Thebesii ;  the  foramen  ovale  in  the  foetus. 

What  can  'you  say  of  the  foramina  of  Tlicbesius  ? 

The  most  of  them  are  blind  sacs.  Some  are,  however,  perforate,  and  return 
blood  from  the  heart  by  the  venae  minimae  cordis.  The  largest  vein  of  this 
group  is  called  the  vein  of  Galen.  You  will  remember  the  veins  of  Galen 
return  the  blood  from  the  basal  ganglia  of  the  brain  to  the  straight  sinus  of  the 
dura  mater.  To  be  specific  in  speech,  then,  speak  of  the  veins  of  Galen  of  the 
brain  and  of  the  heart. 

Name  the  openings  in  the  right  auricle  having  valves. 

The  auriculo-ventricular,  the  coronary  sinus,  and  the  ascending  vena  cava. 


224  PRACTICAL    ANATOMY. 

Name  and  give  the  importance  of  the  openings  of  the  right  ventricle. 

The  auriculo-ventricular  opening,  guarded  by  valves  of  like  name  ;  the 
pulmonary  opening,  at  the  beginning  of  the  pulmonary  artery,  guarded  by  the 
pulmonary  semilunar  valves,  three  in  number. 

What  are  the  sinuses  of  Valsalva  and  u'/iere  do  yon  find  them  in  practical 
anatomy  / 

They  are  pouches  or  dilatations  behind  the  semilunar  valves  of  both  the 
aorta  and  pulmonary  artery. 

What  are  the  c alumna  carnece  / 

They  are  muscular  columns  found  in  the  ventricles  of  the  heart.  They  are 
mechanical  devices  for  -strengthening  the  cardiac  walls.  They  also  give  a 
yielding  attachment  to  the  auriculo-ventricular  valves. 

What  are  the  chordce  tcndime  / 

Strong,  glistening,  tendinous  threads  attached  by  one  extremity  to  the 
auriculo-ventricular  valves,  by  the  other  to  the  walls  of  the  ventricle  by  the 
medium  of  the  columneae  carneae.  They  inhibit  the  movement  of  the  valve 
during  systole  and  aid  recoil  of  the  valve  in  diastole  of  the  ventricles. 

Describe  the  blood-supply  of  the  heart. 

The  heart  is  supplied  with  blood  by  two  arteries,  called  the  left  and  right 
coronary  arteries.  These  arteries  arise  from  the  sinuses  of  Valsalva  of  the  aorta. 
The  left  arises  from  the  posterior  sinus,  the  right  from  the  anterior  sinus.  The 
auriculo-ventricular  grooves  and  the  interventricular  grooves  are  where  you 
will  find  the  main  trunks  of  the  arteries  that  supply  the  heart. 

Two  anastomotic  circles,  a  horizontal  and  a  vertical,  corresponding  to  the 
grooves  separating  the  auricles  from  the  ventricles,  and  the  ventricles  from  each 
other  respectively,  may  be  traced  out.  The  right  coronary  artery  divides  into 
two  main  branches  :  the  horizontal  occupies  the  right  auriculo-ventricular  groove  ; 
the  vertical,  the  right  interventricular  groove.  The  left  coronary  artery  divides 
likewise  into  two  branches:  the  horizontal  one  occupies  the  left  auriculo-ventricular 
groove,  and  the  vertical  the  left  interventricular  groove.  In  these  grooves  the 
opposite  arteries  anastomose. 

HOT.V  is  blood  returned  from  the  heart  / 

Veins  called  coronary  accompany  the  arteries  just  described,  and  open  into 
the  right  auricle  by  the  coronary  sinus,  which  is  guarded  by  the  coronary  valve. 
This  opening  is  between  the  inferior  vena  cava  and  the  auriculo-ventricular 
opening. 


ABDOMEN. 


THE  ABDOMINAL  WALLS. 

Dissection. — Locate  on  the  cadaver  (i)  the  ensiform,  or  metastcrnum  ;  (2)  the 
sympliysis  pubis  ;  (3)  the  spine  of  the  pnbcs  ;  (4)  the  crest  of  the  pubes  ;  (5)  the 
crest  of  the  ilium  ;  (6)  the  anterior  superior  iliac  spine  ;  (7)  the  loiver  eight  ribs  ; 
(8)  the  umbilicus;  (9)  Pouparf 's  ligament ;  (10)  the  mid-line  of  the  abdomen. 

The  abdominal  walls  include  (i)  skin  ;  (2)  superficial  fascia;  (3)  panniculus 
adiposus  ;  (4)  deep  fascia  ;  (5)  the  external  or  descending  oblique  muscle  ;  (6)  the 
internal  or  ascending  oblique  muscle  ;  (7)  the  transversalis  muscle  ;  (8)  the  rectus 
abdominis  ;  (9)  the  pyramidalis  ;  (10)  the  sheath  of  the  rectus;  (i  i)  the  trans- 
versalis fascia;  (12)  the  linea  alba;  (13)  the  lineae  transversae  ;  (14)  the  linese 
semilunares  ;  (i  5)  peritoneum. 

1 .  Define  panniculus  adiposus. 

The  great  mass  of  fat  in  the  upper  strata  of  superficial  fascia  is  thus  desig- 
nated. It  is  of  variable  thickness.  In  it  are  found  the  cutaneous  vessels  and 
nerves  to  the  skin  covering  the  abdomen. 

2.  What  can  you  say  of  the  deep  fascia  ? 

It  is  beyond  doubt  the  same  as  the  aponeurosis  of  the  external  oblique 
muscle.  The  thin  fascia  described  by  some  authors  is  not  continuous  with  the 
fascia  lata,  nor  has  it  attachments  to  bone  ;  hence  it  must  be  the  deep  layer  of 
the  superficial  fascia.  The  aponeurosis  of  the  external  oblique  muscle  is  continu- 
ous with  the  fascia  lata  ;  hence  it  must  represent  the  deep  fascia. 

3.  Define  linea  alba. 

It  is  in  the  mid-line,  extending  from  the  ensiform  cartilage  to  the  symphysis 
pubis.  It  is  the  place  where  the  muscles  of  the  two  sides  of  the  abdomen  meet. 

4.  Hoiv  is  the  sheath  of  the  rectus  formed  f 

By  a  delamination  or  splitting  of  the  aponeurosis  ofthe  internal  oblique  muscle. 
In  front  of  the  muscle,  then,  is  the  entire  thickness  of  the  aponeurosis  of  the 
external  oblique,  and  half  of  the  thickness  of  the  internal  oblique  ;  behind  the 
muscle  is  the  entire  thickness  of  the  transversalis,  and  half  of  the  thickness  of 
the  aponeurosis  of  the  internal  oblique. 

5 .  Does  the  muscle  extend  through  the  sheath  from  end  to  end  in  this  manner  ? 
No  ;    it    perforates   the  posterior   wall    of   its    sheath   midway   between    the 

umbilicus  and  the  pubic  crest,  thus  leaving,  from  this  point  down  to  the  pubic 
crest,  the  three  aponeuroses  all  in  front  of  the  muscle. 

6.  By  what  name  is  the  lower  margin  of  the  posterior  part  of  the  sheath  of  the 
rectus  known  ? 

It  is  called  the  semilunar  fold  of  Douglas. 

Preparation  and  Incisions. — Make  a  circular  incision  through  the  skin,  three 
inches  in  diameter,  around  the  umbilicus  as  the  central  point.  Begin  at  the  cir- 
cumference and  dissect  the  skin  toward  the  umbilicus  for  about  one  inch  all 
around.  Now,  with  a  small  pair  of  scissors  puncture  into  the  peritoneal  cavity 
through  the  center  of  the  umbilicus  ;  insert  a  tube  and  inflate  the  cavity  to  its 

225 


226 


PR  A  C7ICA  L  A  NA  7  OMY. 


Pectoralis  major 


SUPRA  CLA  VICULAR 
BRANCH  OF 
CERVICAL  PLEXUS 


Pectoralis  minor 


-  INTERCOSTO- 
\\  HUMERAL 


—  Latissimua  doisi 


Serratus  magnua 


Sheath  of  rectua 


ANTERIOR 
CUTANEOUS  OF 
LAST  THORACIC 


11:10- 


ILIO-INGTIXM. 


External  oblique 


LATERAL  CUTANEOUS 
OF  LAST  THORACIC 
NERVE 


158. — CUTAM  »i  -    NKKVI-.S  OK  TIIK  THORAX   AMI  ABDOMEN,  \II\VI-D   i  ROM   THK  SIDK.      (Atu-i 

Henle.) 


ABDOMEN. 


227 


fullest  extent,  and  let  an  assistant  throw  a  string  about  the  umbrella  of  skin  just 
turned  upward,  and  while  you   withdraw  the  tube  he  will   tie  the  cord.     The 


Peetoralis  major 


Origin  of  pectoralis 

Major  from  aponeurosis 

of  obliquus  externus 


Obliquua  externue 


Linea  semilunaris 


Tensor  vaginae  femoria 


Ilio-tibial  baud 


TrapeziuB 
Serratus  maguua 


LatissimuB  dorsi 


Oluteui  maximus 


Tendon  of  biceps 


FIG.   159. — EXTERNAL  OBLIQUE  AND  ILIO-TIBIAL  BAND. 

cavity  distended  in  this  way,  you   can   proceed  properly  with  your  dissection  as 
follows  : 

Incisions. — (i)   Cut  from  ensiform  to  symphysis  pubis  ;  (2)  cut  from  umbilicus 


228 


PRACTICAL   ANATOMY. 


horizontally  outward,  at  right  angles  to  the  first  incision.      Remove  the  skin  care- 
fully, beginning  at  the  umbilicus. 


Biceps 


Subscapularis 


Pectoralis  minor 


Pectoralis  major 
Teres  major 


Internal  oblique 


Rectus 


PyramidaliB 
Conjoined  tendon 


FIG.   160.  —  Tin-.  I'K<  IOKAI.IS  MINOR, 


INTERNUS,  PYRAMIDAI.IS,  AND  RECTUS  ARDOMINIS. 


In  this  region  you  will   find:  (i)  The  cutaneous  branches  of  the  six  lower 
intercostal   nerves  ;   (2)  the  ilio-hypogastric  nerve  ;  (3)  the  ilio-inguinal   m-r\  v  ; 


ABDOMEN. 


229 


(4)  the  spermatic  cord  with  the  genital  branch  of  the  genito-crural  nerve  on  its 
posterior  surface  and  the  ilio-inguinal  nerve  in  front;  (4)  you  will  see  also  with 
the  above  abdominal  intercostal  nerves  some  small  arteries.  They  are  the  lower 
intercostals  and  lumbars. 

The  nerves  you  see  near  the  mid-line  (Fig.  158)  are  the  terminal  branches, 
while  those  represented  more  externally  are  the  lateral  cutaneous  branches  of  the 
intercostals.  Search  in  the  fat  until  you  find  the  point  of  emergence  of  the  nerve  ; 
then  trace  out  its  branches  by  dividing  the  connective  tissue  in  the  direction  of 
the  branches. 

External  Oblique  (Fig.  159). — (i)  Dissect  the  fat  and  fascia  off  and  expose 
the  muscle  as  in  the  figure.  At  the  upper  part  of  the  muscle  develop  the  digi- 
tations  of  this  muscle  with  the  serratus  magnus.  Trace  each  digitation  to  the 
bone.  In  developing  these  origins  use  the  forceps  and  scissors.  (2)  Now  trace 


Aponeurosis 
of  obliquus 
externua 


Loops  of  — | 
eremaster 


Intercolumnar 
fibres 


FIG.  161. — OBLIQUUS  EXTERNUS  AND  FASCIA  LATA. 


the  muscle  downward  and  forward  in  the  direction  of  the  fibres  to  the  outer  lip 
of  the  iliac  crest.  Notice  that  the  muscular  fibres  disappear  at  the  anterior 
superior  iliac  spine,  and  from  this  point  onward  to  the  mid-line  of  the  abdomen, 
and  downward  to  the  pubes,  the  muscle  is  continued  as  an  aponeurosis — /.  e., 
the  muscle  minus  the  lean  meat !  (3)  Remove  the  fat  and  fascia,  and  demon- 
strate the  linea  semilunaris,  the  lineae  transversae,  and  the  linea  alba.  The  last 
is  in  the  mid-line.  (4)  Examine  the  lower  margin  of  the  aponeurosis  of  this 
external  oblique  muscle.  It  extends  in  a  sagging  manner  from  the  anterior 
superior  iliac  spine  to  the  pubic  spine  under  the  name  of  Poupart's  ligament,  or 
crural  arch.  This  arch  is  continuous  below  with  the  fascia  lata  of  the  thigh. 
(5)  Locate  the  spine  of  the  pubes,  and  on  the  under  part  of  the  same  find  the 
spermatic  cord.  (Fig.  161.)  Trace  this  cord  upward  and  outward  to  a  point 
where  it  enters  the  external  abdominal  ring.  (Fig.  161.)  Above  and  below  the 
ring,  see  the  pillars  or  columns  of  the  ring.  Notice  and  develop  some  transverse 


230 


PRACTICAL  ANATOMY. 


fibres,  called  the  intercolumnar  fibres.  (6)  Insert  the  forceps  between  the  pillars 
just  mentioned,  parallel  to  Poupart's  ligament,  for  about  two  inches.  They  are 
now  in  the  inguinal  canal.  (Fig.  163.)  Below  them  is  the  floor  of  the  canal, — the 
upper  surface  of  Poupart's  ligament, — and  on  this  floor  is  the  spermatic  cord  ; 
external  to  them  is  the  outer  wall  of  the  canal — the  aponeurosis  of  the  external 
oblique  muscle  ;  above  them  is  the  roof  of  the  canal — the  arched  fibers  of  the 
internal  oblique  and  transversalis  muscles  ;  internal  to  them  is  the  inner  wall  of 
the  canal — the  conjoined  tendon  of  the  internal  oblique  and  transversalis  muscles 
and  the  transversalis  fascia.  If  you  gently  pull  the  spermatic  cord,  you  will  see 
where  it  comes  into  view.  This  spot  where  the  cord  appears  is  the  internal 


External  intercostal 


Internal  intercostal 


Posterior  portion  of 
sheath  of  reotua 


Transversalis 
abdoininis 


Fold  of  Douglaa 

Iliaous 

Transversalis  fascia  and 
internal  abdominal  ring 

Conjoined  tendon 

Poupart's  ligament 

Gimbernat's  ligament 


Serratua  magnus 


Lumbar  fascia 


FIG.  162. — TRANSVERSALIS  ABDOMJNIS  AND  SHEATH  OK  RKCTUS. 


abdominal  ring  in  the  transversalis  fascia.      Do  not  remove  the  forceps  until  you 

have  re-read  (6), — i,  e.,  the  above  geometrical  description   of  the  inguinal  canal, 

— and  carefully  studied. and  learned  the  following: 

The  inguinal  canal  has  the  following  points  : 

1.  An  external  ring  in  the  aponeurosis  of  the  external  oblique.      (Fig.  161.) 

2.  An  internal  ring  in  the  transversalis  fascia. 

3.  A  floor,  the  upper  inner  surface  of  Poupart's  ligament. 

4.  A  roof,  the  arched  fibres  of  the  internal  oblique  and  transversalis. 

5.  An  outer  ,\v?//,  the  aponeurosis  of  the  external  oblique. 

6.  An  inner  aW/,  conjoined  tendon,  triangular  ligament,  transversalis  fasc 

7.  Contents:    spermatic  cord,  male  ;   round  ligament,  female. 


ABDOMEN. 


231 


8.  Extent,  from  external  to  internal  abdominal  ring. 

9.  Location  of  internal  ring,  one-half  of  an  inch  above  Poupart's  ligament  and 
midway  between  symphysis  pubis  and  anterior  superior  iliac  spine. 

10.   Length  of  canal,  one  and  one-half  inches. 

Having  learned  the  above  thoroughly,  cut  through  the  external  wall  and 
expose  the  canal,  as  in  figure  161. 

Coverings  of  the  Spermatic  Cord  and  Testicle. — Pass  your  finger  down 
into  the  scrotum  anterior  to  the  cord  ;  cut  through  the  skin  and  fascia  and 
expose  the  testicle  and  find  the  following  coats  : 

1.  The  skin  and  superficial  fascia. 

2.  The  dartos,  consisting  of  muscular  and  contractile  tissue. 

3.  The  intercolumnar  fascia,  part  of  external  oblique. 

4.  The  cremasteric  fascia,  part  of  the  internal  oblique. 

5.  The  infiindibuhnn,  part  of  transversalis  fascia. 

6.  The  tunica  vaginalis,  part  of  the  peritoneum. 

You  will  then  look  upon  these  coats  as  small  parts  of  the  individual  con- 
stituents of  the  abdominal  walls  pushed  ahead  of  the  testicle  in  its  descent. 
The  tunica  vaginalis  was  pushed  ahead,  a  part  of  the  peritoneum  ;  the  infundi- 
bulum,  a  part  of  the  transversalis  fascia;  the  cremaster,  apart  of  the  internal 
oblique  ;  the  intercolumnar  fascia,  a  part  of  the  external  oblique  ;  the  dartos,  a 
part  of  the  superficial  fascia,  slightly  modified  by  the  presence  of  elastic  fibres 
and  muscle  fibres  ;  the  skin  to  form  the  scrotum. 

The  Spermatic  Cord. — In  front  of  the  cord  find  the  ilio-inguinal  nerve  ;  be- 
hind the  cord  the  genital  branch  of  the  genito-crural  nerve.  Find  the  excretory 
duct  of  the  testicle — the  vas  deferens  ;  the  spermatic  artery,  a  branch  of  the 
aorta  ;  the  spermatic  veins  ;  a  little  artery — the  deferential — in  the  sheath  of  the 
vas  deferens.  These  structures  are  all  bound  loosely  together  by  connective 
tissue.  You  will  trace  all  these  structures  to  the  testicle. 

Next  expose  the  internal  oblique  muscle  by  turning  aside  the  external  ob- 
lique in  this  manner  :  Divide  the  digitations  at  their  attachments  into  the  eight 
lower  ribs.  Turn  the  whole  muscle  forward  and  see  the  internal  oblique.  Its 
fibres  run  upward  and  inward.  This  is  also  called  ascending  oblique. 

The  Internal  Oblique  (Fig.  160). — This  muscle  has  attachments :  (i)  To 
the  outer  surface  of  the  four  lower  ribs  ;  (2)  to  the  middle  lip  of  the  crest  of  the 
ilium  ;  (3)  to  the  outer  one-half  of  Poupart's  ligament ;  (4)  to  the  pubic  crest 
and  ilio-pectineal  line  ;  (5)  to  the  linea  alba.  Notice,  first,  the  arch  formed  by  this 
muscle  and  the  transversalis.  In  figure  160  you  see  these  muscles  are  attached 
to  Poupart's  ligament  for  about  the  outer  one-half  the  length  of  this  ligament; 
then  they  leave  this  ligament,  arch  over  the  cord,  form  the  roof  of  the  inguinal 
canal,  and  are  inserted  into  the  pubic  crest  by  the  conjoined  tendon.  Trace  this 
muscle  to  the  middle  lip  of  the  iliac  crest,  anterior  two-thirds. 

Make  an  incision,  parallel  to  the  iliac  crest,  through  this  muscle,  and  you  will 
come  down  upon  the  neuro-vascular  area  of  the  abdominal  walls.  These  vessels 
and  nerves  are  between  the  internal  oblique  and  transversalis,  in  a  small  quantity 
of  fatty  connective  tissue,  and  are  as  follows  : 

1.  Deep  circumflex  iliac  artery,  from  the  external  iliac. 

2.  Ilio-hypogastric  nerve,  from  the  lumbar  plexus. 

3.  Ilio-inguinal  nerve,  from  the  lumbar  plexus. 

4.  Lower  intercostal  nerves,  the  twelfth  thoracic. 

It  will  require  care  to  separate  these  muscles.  The  guide  is  this  :  Keep  the 
nerves  in  sight  and  follow  them.  Now  trace  the  internal  oblique  muscle  to  the 
outer  surface  of  the  four  lower  ribs.  Notice  the  direction  taken  by  the  muscular 
fibres.  See  also  that  the  fibres  of  this  muscle  are  attached  to  the  outer  one-half 
of  Poupart's  ligament,  with  the  transversalis,  and  that  both  are  inserted  by  a 


232  PRACTICAL    ANATOMY. 

conjoined  tendon  into  the  pubic  crest  and  ilio-pectineal  line  for  a  variable  dis- 
tance. 

The  transversalis  muscle  is  now  fully  exposed  to  view.  (Fig.  162.)  On 
its  outer  surface  you  see  the  plexus  of  nerves  and  the  vessels  previously  described. 
On  its  inner  surface  you  will  find  the  transversalis  fascia.  The  fibres  of  this 
muscle  extend  transversely  across  the  wall.  The  muscle  arises  (i)  from  the 
inner  surfaces  of  the  six  lower  ribs,  interdigitating  with  the  diaphragm  ;  (2)  from 
the  lumbar  fascia ;  (3)  from  the  inner  lip  of  the  iliac  crest ;  (4)  from  the  outer 
two-thirds  of  Poupart's  ligament.  The  muscle  is  inserted  into  (i)  the  lineaalba  ; 
(2)  the  crest  of  the  pubes  ;  (3)  the  ilio-pectineal  line.  This  muscle  assists  the 
internal  oblique  in  forming  the  arch  and  the  conjoined  tendon. 


FIG.  163. — INTERNAL  OBLIQUE  AND  TRANSVERSALIS  ABDOMINIS  MUSCLES. 

I,  I.  Rectus  abdominis.  2,  2.  Internal  oblique.  3,  3.  Anterior  leaflet  of  aponeurosis  of  internal  oblique. 
4,  4.  Divided  external  oblique.  5,  5.  Spermatic  cords.  6,  6.  Inferior  portion  of  aponeurosis  of 
external  oblique.  7.  Lower  portion  of  left  rectus  abdominis;  upper  portion  removed.  8,8.  Mus- 
cular portion  of  transversalis  abdominis.  9.  Aponeurotic  portion,  to.  Umbilicus.  II.  Supra 
umbilical  portion  of  linea  alba.  12.  Infra-umbilical  portion.  13.  Senatus  magnus.  14.  Divided 
right  latissimus  dorsi.  15-  Divided  left  latissimus  dorsi.  16.  Divided  serratus  magnus.  17,  17. 
External  intercostals.  18,  18.  Femoral  aponeurosis.  19.  Divided  internal  oblique. 

The  Rectus  and  Pyramidalis. — Make  an  incision  through  the  sheath  of 
the  rectus,  extending  from  the  pubic  spine  to  the  fifth  rib,  parallel  with  the  linea 
alba.  Carefully  dissect  the  sheath  both  ways — /.  c.,  turn  the  sheath  to  the  right 
and  left — until  you  have  fully  exposed  the  muscular  contents.  (Fig.  160.)  The 
white  lines  crossing  the  rectus  are  the  linear  transverse.  You  will  find  the  pyra- 
midalis  below,  arising  from  the  pubic  crest  in  front  of  the  rectus.  Trace  it  to  its 
insertion  into  the  linea  alba.  (Fig.  160.)  Now  you  can  easily  lift  the  rectus  from 
its  bed,  and  look  down  on  the  posterior  part  of  its  slie.ith.  (Fig.  163.)  A  descrip- 
tion of  the  formation  of  the  sheath  is  given  in  the  beginning  of  this  section.  Cut 
through  the  rectus  one  inch  below  the  umbilicus  and  see  :  (i)  The  deep  epigastric 
artery  and  its  veins  ;  (2)  the  sanilniiar  fold  <>/'  /)t>ttg/ds.  Turn  the  divided  ends 
of  the  rectus  aside  and  trace  out  the  branches  of  the  deep  epigastric  artery. 


ABDOMEN.  233 

Hesselbach's  triangle  is  of  surgical  importance  because  direct  inguinal  hernia 
passes  through  it.  (Fig.  165.)  It  is  bounded  internally  by  the  rectus,  externally  by 
the  deep  epigastric  artery,  below  by  Poupart's  ligament.  See,  now,  that  the  con- 
joined tendon  of  the  internal  oblique  and  transversalis  stretches  across  the  inner 
two-thirds  of  this  triangle.  Hence  this  tendon  may  become  one  of  the  coverings 
of  a  direct  inguinal  hernia. 

1 .  Points  of  surgical  interest. 

The  inguinal  canal,  since,  physiologically,  it  transmits  the  male  spermatic  cord 
and  its  homologue,  the  round  ligament  of  the  uterus  ;  since,  pathologically,  in- 
guinal hernia  and  diseases  of  the  cord  are  interrogated  here. 

2.  Importance  of  tlie  umbilictts. 

This  is  a  physiological  cicatrix  or  scar,  marking  the  aperture  through  which 
passed  the  vessels  that  made  up  the  umbilical  cord,  or  funis,  in  the  child  before 
birth.  These  vessels  were  the  right  and  left  hypogastric  arteries  (branches  of  the 
internal  iliacs)  and  the  umbilical  vein.  The  arteries  took  blood  to  the  placenta 
for  aeration  ;  the  vein  returned  this  blood  aerated.  You  will  find  internally  in 
adult  dissections  remains  of  these  three  vessels  centering  at  the  umbilicus. 

3 .  Further  importance  of  umbilicus. 

In  both  adult  and  child  it  may  be  the  location  of  umbilical  hernia. 

4.  Give  nerve-supply  of  the  abdominal  muscles. 

The  six  lower  thoracic  nerves,  through  their  anterior  primary  divisions, 
assisted  by  the  ilio-hypogastric  and  ilio-inguinal  nerves  from  the  lumbar  plexus. 
They  also  supply  the  skin  covering  these  muscles. 

5 .  Give  the  blood-supply  of  the  abdominal  ivalls. 

This  is  both  abundant  and  important,  (i)  The  deep  epigastric  ;  (2)  the  internal 
mammary  ;  (3)  the  lumbar  arteries  ;  (4)  the  intercostals  ;  (5)  the  deep  circum- 
flex iliac  ;  (6)  the  superficial  circumflex  iliac  ;  (7)  the  superficial  epigastric.  The 
deep  epigastric,  a  branch  of  the  external  iliac,  anastomoses  in  the  substance  of 
the  rectus  muscle  with  the  superior  epigastric  branchof  the  internal  mammary 
artery,  a  branch  of  the  subclavian  artery. 

6.  Function  of  abdominal  muscles. 

(i)  They  protect  from  violence  and  temperature  changes  the  organs  in  the 
abdominal  cavity  ;  (2)  they  assist  internal  organs  to  discharge  their  contents,  in 
that  they  excite  peristalsis — a  physiological  Crede  ;  (3)  they,  by  their  various 
contractions,  alter  the  relations  between  the  thorax  and  abdomen  ;  (4)  they  are 
strongly  analogous  to  structures  above  the  diaphragm.  The  external  oblique  is 
analogous  to  the  external  intercostals  ;  the  internal  oblique  to  the  internal  inter- 
costals ;  the  transversalis  to  the  triangularis  sterni ;  the  rectus  to  the  sternum  ; 
the  linese  semilunares  to  the  chondra,  vertically  ;  the  lineae  transversae  to  the  cos- 
tal cartilages  ;  their  nerve-  and  blood-supply  are  strongly  analogous,  while  func- 
tions conform  to  local  demands  and  structure  is  modified  accordingly. 

Important  Attachments  and  Relations. — Notice  carefully  the  following,  and 
demonstrate  on  your  dissection  the  following  points  : 

1.  Each  of  the  three  broad  muscles  has  (i)  an  outer  muscular  part,  and  (2) 
an  inner  aponeurotic  part ;  the  latter  are  inseparably  united,  the  former  may  be 
separated  from  each  other. 

2.  The  conjoined  aponeuroses  of  all  three  planiform  muscles  form  the  verti- 
cal mid-line  of  the  abdominal  walls,  known  as  linea  alba  abdominis. 

3.  The  two  inner  muscles  are  attached  to  the  upper  surface  of  Poupart's 
ligament  for  about  one-half  the  length  of  this  (the  outer  one-half),  and  then  leaving 
the  same  arch  over  the  spermatic  cord,  forming  the  roof  of  the  inguinal  canal,  and 
are  inserted  into  the  pubic  crest  and  inner  part  of  the  ilio-pectineal  line. 

4.  Between    the   muscular  parts  of  the   internal    oblique   and   transversalis 
muscles  is  located  a  meagre  plexus  of  nerves,  from  which  the  abdominal  muscles 

16 


234  PRACTICAL  ANATOMY. 

are  supplied.     The  deep  internal  circumflex  artery  and  its  veins  are  also  found 
here. 

5 .  Give  the  origin  and  insertion  of  the  external  oblique. 

Origin. — The  outer  surface  of  the  eight  lower  ribs  about  their  middle  by  a 
series  of  nearly  horizontal  lines  which,  after  crossing  each  rib  obliquely  down- 
ward and  backward,  extend  for  a  short  distance  along  its  lower  border. 

Insertion. — (i)   By  a  strong  aponeurosis  along  the  whole  of  the  linea  alba; 

(2)  the  front  of  the  os  pubis  close  to  the  symphysis  ;  (3)  the  spine  of  the  pubes 
and  the  adjacent  part  of  the  ilio-pectineal  line  ;  (4)  the  deep  fascia  of  the  thigh 
in  a  thickened  band  which  stretches  from  the  spine  of  the  pubes  to  the  anterior 
superior  spine  of  the  ilium  ;  (5)  the  anterior  half  of  the  outer  lip  of  the  crest  of 
the  ilium  ;  (6)  at  the  lower  part  of  the  linea  alba  some  of  the  fibres  (the  trian- 
gular fascia]  stretch  across  the  middle  line,  and  are  inserted  into  the  front  of  the 
crest  of  the  pubes  and  the  inner  part  of  the  ilio-pectineal  line  of  the  other  side. 

6.  Give  origin  and  insertion  of  internal  oblique. 

Origin. — (i)  The  outer  half  of  Poupart's  ligament ;  (2)  the  anterior  two-thirds 
of  the  space  intervening  between  the  inner  and  outer  lips  of  the  crest  of  the  ilium  ; 

(3)  the  outer  and  posterior  aspect  of  the  aponeurosis  of  the  transversalis  abdom- 
inis  (which  aponeurosis  is  also  called  the  lumbar  fascia). 

Insertion. — (i)  For  about  one  inch  into  the  inner  extremity  of  the  ilio-pecti- 
neal line  ;  (2)  the  anterior  border  of  the  crest  of  the  pubes  ;  (3)  the  whole  length 
of  the  linea  alba ;  (4)  the  lower  borders  of  the  cartilages  of  the  last  three  ribs. 

7.  Give  origin  and  insertion  of  transversalis. 

Origin. — (i)  The  inner  surface  of  the  cartilages  of  the  last  six  ribs,  close  to 
their  junction  with  the  ribs,  by  processes  which  interdigitate  with  the  attachments 
of  the  diaphragm  ;  (2)  the  strong  aponeurosis  called  the  lumbar  fascia,  which  arises 
(a)  by  its  anterior  layer  from  the  front  of  the  transverse  processes  of  the  five 
lumbar  vertebrae,  (^)  by  its  middle  layer  from  the  tips  of  the  transverse  processes 
of  the  five  lumbar  vertebrae,  (c]  by  its  posterior  layer  from  the  general  vertebral 
aponeurosis  which  is  attached  to  the  spines  of  the  thoracic,  lumbar,  and  sacral 
vertebrae  ;  (3)  the  anterior  two-thirds  of  the  inner  lip  of  the  crest  of  the  ilium  ; 

(4)  the  outer  third  of  Poupart's  ligament. 

Insertion. — (i)  The  whole  length  of  the  linea  alba ;  (2)  the  anterior  border  of 
the  crest  of  the  pubes  ;  (3)  the  inner  end  of  the  ilio-pectineal  line  for  about  one 
inch  and  a  half. 

8.  Give  origin  and  insertion  of  the  rectus. 

Origin. — By  two  tendons:  (i)  The  larger  or  outer  head  arises  from  the 
whole  of  the  crest  of  the  pubes  ;  (2)  the  inner  head  crosses  the  middle  line  of 
the  body,  and  arises  from  the  fibrous  structures  lying  in  front  of  the  symphysi> 
pubis. 

Insertion. — (i)  The  anterior  surface  of  the  tip  of  the  fifth  rib  ;  (2)  the  front  ot 
the  costal  cartilages  of  the  fifth,  sixth,  and  seventh  ribs  ;  sometimes  also  (3)  th< 
deep  posterior  surface  of  the  ensiform  cartilage  near  its  outer  border. 

Anatomy  of  Inguinal  Hernia. — There  are  two  varieties  of  inguinal  hernia, 
founded  on  the  idea  of  internal  to  or  external  to  the  deep  epigastric  artery,  a 
structure  already  seen  in  your  dissection.  The  name  direct  inguinal  is  given 
when  a  hernia  comes  through  Hesselbach's  triangle.  In  this  case  the  coverings 
are:  (i)  Peritoneum  ;  (2)  transversalis  fascia ;  (3)  conjoined  tendon;  (4)  inter- 
columnar  fascia ;  (5)  superficial  fascia ;  (6)  skin.  The  name  oblique  is  given 
when  the  hernia  enters  the  canal  by  the  internal  abdominal  ring,  in  the  transver- 
salis  fascia,  external  to  the  deep  epigastric  artery.  It  has  these  coats  :  (i)  Peri- 
toneum ;  (2)  subserous  fatty  connective  tissue  ;  (3)  infundibulum  ;  (4)  cremasteric 
muscle;  (5)  intercolumnar  fascia  ;  (6)  superficial  fascia  ;  (7)  skin.  This  variety 
of  hernia  follows  the  course  taken  by  the  testicle  in  its  descent,  and  receives  the 


ABDOMEN. 


235 


same  kind  of  investments.  As  before  stated,  these  coats  are  simply  certain  parts 
of  the  walls  which  have  receded  before  the  hernia  in  its  descent. 

Describe  tJic  ilio-liypogastric  nerve. 

It  is  a  branch  of  the  lumbar  plexus.  It  is  known  also  as  the  superior  mus- 
culo-cutaneous  nerve.  It  crosses  the  quadratus  lumborum  muscle,  gains  the 
space  between  the  transversalis  and  internal  oblique  muscles,  and  divides  into  (i) 
an  iliac  branch,  which  supplies  the  skin  over  the  gluteal  region  ;  (2)  a  terminal 
hypogastric  branch,  that  passes  between  these  two  muscles — i.  c\,  the  internal 
oblique  and  transversalis — to  near  the  mid-line,  where  it  comes  through  the 
abdominal  walls  an  inch  above  the  external  abdominal  ring. 

Describe  the  ilio-inguinal  nerve. 

You  find  this  nerve  anterior  to  the  spermatic  cord.      It  is  distributed  to  the 


Epigastric  artery 


Internal  abdom- 
inal ring 


Border  of  the 
posterior  part 
of  the  sheath 
of  the  reetus 
(fold  of  Doug- 
las) 

Posterior  surface 
of  reetus 


'Jjitf Conjoined  tendon 

in   the    triangle 


of  Hesselbach 
Obliterated  hypo- 
gastric  artery 
Lymphatics  in 
crural  rings 


External  iliac  artery 

FIG.  164. — DISSECTION  OF  THE  LOWER  PART  OF  THE  ABDOMINAL  WALL  FROM  WITHIN,  THE  PERI- 
TONEUM  HAVING   BEEN   REMOVED.       (Wood.) 

scrotum  and  labia  majora,  and  to  the  inner  and  upper  part  of  the  thigh.  It  is  a 
branch  of  the  lumbar  plexus.  It  runs  near  to  and  plexifies  with  the  preceding 
nerve,  between  the  internal  oblique  and  transversalis. 

Describe  t/te  genilo-crural  nerve. 

This  is  seen  behind  the  spermatic  cord,  in  the  canal  ;  after  the  cord  emerges 
from  the  external  abdominal  ring,  the  genital  branch  of  the  genito-crural  nerve  is 
seen  behind  the  cord.  This  supplies  the  cremaster  muscle  with  motion.  The 
crural  branch  of  the  genito-crural  nerve  goes  to  the  skin  over  the  mid-front  of 
the  thigh  half  way  to  the  knee. 


INTERIOR  VIEW  OF  ABDOMINAL  WALLS. 

Make  an  incision  on  each  side,  from  the  lower  part  of  the  umbilicus  to  the 
anterior  superior  spine  of  the  ilium,  through  the  entire  remaining  abdominal  wall. 
Turn  the  V-shaped  flap  thus  formed  forward,  and  at  the  same  time  lift  it  upward 


236  PRACTICAL  AX  A  TO  MY. 

and  put  it  on  the  stretch  as  much  as  possible.     You   are  to  see  and   study  the 
following  structures  through  the  peritoneum  (do  not  remove  this  yet) : 

1.  The  plica  urachi — a  peritoneal  fold  covering  the  remains  of  the  urachus. 
This  is  in  the  mid-line  from  the  summit  of  the  bladder  to  the  umbilicus. 

2.  The  plica  hypogastrica,  covering  the  remains  of  the  hypogastric  arteries. 

3.  The  deep  epigastric  arteries  and  veins,  passing  upward  and  inward  to 
enter  the  sheath  of  the  rectus  muscle  by  passing  under  the  fold  of  Douglas. 

4.  Poupart's  ligament  and  the  external  iliac  vessels  leaving  the  pelvis,  to 
be  called  femoral  in  the  thigh.      Here,  too,  see  the  external  iliac  artery  giving  oft" 
its  two  branches,  the  deep  epigastric  and  the  internal  circumflex  iliac  branch. 

5.  The  internal  abdominal  ring,  to  which  you  may  see  plainly  the  con- 
stituents of  the  spermatic  cord  coming — viz.,  the  vas  deferens,  the  spermatic 
vessels.     Locate  this  ring  just  to  the  outer  side  of  the  deep  epigastric  artery. 

6.  The  femoral  canal,  called  also  crural  canal.     Find  this  to  the  inner  side 
of  the  femoral  vein,  between  Poupart's  ligament  above  and  the  bone  below.     To 
its  inner  side  you  will  feel  the  sharp  falciform  margin  of  Gimbernat's  ligament. 
This  canal  is  in  the  femoral  sheath,  and  occupied  by  fat  and  connective  tissue 
called  the  septum  crurale  or  septum  femorale. 

7.  Inguinal  and  Femoral  Fossae. — There  are  three  of  these.     The  internal 
is  between  the  remains  of  the  urachus  and  hypogastric  artery  ;  the  middle  inguinal 
fossa  is  between  the  remains  of  the  hypogastric  artery  and  the  deep  epigastric 
artery.      The  importance  of  these  two  fossae   is    they  permit   direct   inguinal 
hernia  to  form.     The  external  inguinal  fossa  is  external  to  the  deep  epigastric 
artery  and  corresponds  to  the  situation  of  the  internal  abdominal  ring,  and  is  the 
location  of  oblique  inguinal  hernia.      In  this  connection  notice  the  femoral  fossa. 
This  corresponds  to  the  femoral  ring,  and  marks  the  location  of  femoral  hernia. 

DISSECTION  OF  FEMORAL  HERNIA. 

Find  the  femoral  fossa,  covered  by  peritoneum,  just  below  Poupart's  liga- 
ment, and  internal  to  the  femoral  vein.  Now  remove  the  peritoneum,  by  pulling 
the  same  gently  backward  and  downward.  Take  the  forceps  and  break  up  the 
connective  tissue  in  the  femoral  canal,  the  depression  corresponding  to  the 
femoral  fossa  just  mentioned  and  internal  to  the  femoral  vein.  We  will  consider 
femoral  hernia  with  reference  to  (i)  the  femoral  sheath  ;  (2)  the  femoral  canal ;  (3) 
the  coverings  of  femoral  hernia  ;  (4)  contents  of  the  canal  ;  (5)  the  relations  to 
other  structures  ;  (6)  anatomical  factors  concerned  in  reduction  ;  (7)  the  deep 
crural  arch. 

The  femoral  sheath  is  formed  under  Poupart's  ligament  by  the  meeting 
and  union  of  the  fascia  transversalis  in  front  of  the  femoral  vessels  and  of  the  iliac 
fascia  behind  the  femoral  vessels.  As  you  will  demonstrate  on  your  cadaver,  these 
fasciae  unite  on  the  outer  side  of  the  femoral  artery  very  close  to  the  vessel ;  on 
the  inner  side  of  the  vein,  however,  they  leave  an  interval,  one-half  of  an  inch  in 
width,  between  the  femoral  vein  and  Gimbernat's  ligament.  (Fig.  165.)  This 
interval  is  the  femoral  canal. 

The  deep  crural  arch  extends  in  an  archiform  manner  across  the  femoral 
sheath,  strengthening  thereby  the  transversalis  fascia.  It  is  inserted  into  the 
spine  of  the  pubes,  and  may  be  looked  upon  as  a  slip  of  contribution  from  the 
transversalis  fascia. 

The  femoral  sheath  contains  the  following  structures  :  ( i)  The  femoral  arte 
on  the  outer  side;  (2)  the  femoral  vein  in  the  middle:  (3)  the  femoral  can 
internal  to  the  vein.     The  beginning  of  the  femoral  canal — not  the  beginning  o 
the  sheath — is  the  femoral   ring.      The  femoral  canal  contains  some  connective 
tissue  that  you  just  broke  up  with  your  forceps.     The  special  name  for  this  is 


the  septum  femorale  or  septum  crurale.      Make  note  of   this,  for  it  forms  one  of 
the  coverings  of  femoral   hernia.      I   wish  to  make  emphatic  the  difference  nou 
between  the  contents  of  the  femoral  sheath  and  the  contents  of  the  femoral  canal. 
The  canal  itself  is  in  the  sheath. 

The  femoral  ring  and  its  relations  are  the  beginning  of  the  femoral  canal, 
just  as  the  brim  is  the  beginning  of  a  cup.  The  ring  has  certain  definite  bounda- 
ries and  relations,  which  you  must  both  demonstrate  on  your  work  and  commit 
thoroughly  to  memory.  In  figure  165  you  can  study  these.  Internal  to  the 
ring  is  the  sharp  falciform  edge  of  Gimbernat's  ligament.  This,  as  you  can  easily 
demonstrate  on  your  work,  is  a  reflection  of  Poupart's  ligament  on  to  the  ilio- 
pectineal  line.  To  the  outer  side  of  the  ring  is  the  femoral  vein.  Above  the 


Deep  circumflex  iliac  artery 

External  iliac  artery 
External  iliac  vein 

Obturator  foramen 


B 


Internal  ring,  with  spermatic 
vessels  cut  short  in  it 

Deep  epigastric  artery 


Lymphatic  gland  in  femoral 
ring 

The  obturator  artery,  given  off" 
from  the  external  iliac  with  the 
deep  epigastric,  descends  to  gain 
the  obturator  foramen,  but  at  a 
safe  distance  from  the  femoral 
ring 


The  obturator  artery,  coming  off" 
from  the  deep  epigastric,  HUM 
a  course  so  near  to  the  femoral 
ring  that  it  would  very  likely 
be  divided  by  the  bistoury  intro- 
duced front  without  to  diritlr-. 
the  base  of  Gimbernaf's  liga- 
ment, the  cause  of  the  constric- 
tion 


FIG.  165. — IRREGULARITIES  OF  THE  OBTURATOR  ARTERY.     (After  Gray.) 


ring  is  Poupart's  ligament.  Below  the  ring  is  the  horizontal  part  of  the  os  pubis, 
covered  by  the  pectineus  muscle  and  its  aponeurosis.  You  will  also  see  the  deep 
epigastric  artery  arising  from  the  femoral  artery  and  passing  upward  and  inward 
across  the  upper  part  of  the  femoral  ring.  In  a  certain  number  of  cases  the 
deep  epigastric  artery  gives  off  the  obturator  artery,  which  passes  either  to  the 
outer  side  of  the  ring,  as  in  A,  figure  165,  or  to  the  inner  side,  as  in  B.  In 
either  case  it  would  complicate  an  operation  for  reduction  of  femoral  hernia. 
You  will  note  on  the  cadaver  that  the  obturator  artery  and  nerve  lie  on  the 


238 


PRACTICAL  ANATOMY. 


outer  wall  of  the  pelvis.  The  artery  is,  as  a  rule,  a  branch  of  the  internal  iliac. 
It  forms  an  exception  to  the  rule  in  the  figures  given  here. 

The  coverings  of  femoral  hernia  from  within  outward  are:  (i)  The  perito- 
neum ;  (2)  the  subperitoneal  connective  tissue  ;  (3)  the  septum  femorale  ;  (4)  the 
femoral  sheath  ;  (5)  the  cribriform  fascia — the  deep  layer  of  superficial  fascia  that 
covers  the  saphenous  opening  in  the  fascia  lata  ;  (6)  the  superficial  fascia  ;  (7)  the 
skin. 

Factors  concerned  in  reduction  of  hernia  are  those  that  tend  to  tighten  the 
canal.  These  are  :  (i)  The  saphenous  opening  ;  (2)  the  iliac  and  pubic  portions 
of  the  fascia  lata ;  (3)  the  external  oblique  muscle  and  its  lower  portion — Pou- 
part's  ligament.  These  structures  that  tend  to  strengthen  a  succession  of  ana- 
tomical weak  points,  determining  the  course  of  a  femoral  hernia,  may  all  be  dis- 
empowered  by  flexion  of  the  thigh  on  abdomen  ;  flexion  of  leg  on  thigh  ;  adduc- 
tion of  thigh.  Demonstrate  this  on  your  work  by  placing  your  finger  in  the 
femoral  canal,  and  let  an  assistant  produce  first  abduction  and  extension,  and 
adduction  and  flexion,  when  the  scissor-like  action  of  Poupart's  and  Gimbernat's 
will  be  appreciated. 


THE  PERITONEUM. 

The  inquisitive  student  instinctively  asks  himself  the  following  simple  ques- 
tions, which  I  will  here  answer  fully  enough  for  dissecting-room  purposes  : 
i .    What  kind  of  a  structure  is  peritoneum  and  ivhere  is  it  fou)id  / 
Peritoneum  is  a  serous  membrane  found  in  the  abdominal  cavity  only. 


LACTEALS 


Veins 


FIG.  166. — VESSELS  OK  THE  SMALL  INTESTINE. 


2.  What  is  the  appearance  of  peritoneum  ami  Jiow  may  I  recogitize  /// 
Peritoneum  is  smooth,  moist,  glistening.     You  can  recognize  it  by  its  loca- 
tion and  its  appearance.      Its  most  distinctive  feature  is  its  location  in  the  abdom- 
inal cavity  ;  removed  from  this  cavity  you  could  not  distinguish  it  from  other 

erous  membranes — pleura  and  pericardium. 

3.  \Vliere  will  f  sec  peritoneum  on  opening  the  abdominal  cavity  / 

You  will  see  it  forming  the  innermost  layer  of  the  wall  you  cut  and  turned 


ABDOMEN. 


239 


back — smooth,  moist,  glistening,  and  attached  ;  you  will  see  it  covering  every 
organ  in  the  abdominal  cavity  partially  or  completely.  If  by  force  of  circum- 
stance organs  lose  all  or  some  of  their  peritoneal  covering,  this  is  no  fault  of  the 
peritoneum.  Remember,  the  primitive  relation  of  every  organ  to  peritoneum  is 
behind — partially  or  completely  covered  thereby.  (Figs.  167  and  168.) 

Figure  167  shows  aorta  giving  three  branches  to  three  organs.  The  organ  in 
the  centre  is  for  practical  purposes  completely  invested  by  peritoneum.  Between 
the  two  parts  of  the  peritoneal  fold  is — (i)  The  organ  ;  (2)  the  vessels  that  take 
blood  to  and  from  the  organ  ;  (3)  the  nerves  that  innervate  the  organ  ;  (4)  the 


VISCERAL  LAYER  OF  PERITONEUM 

PERITONEAL  CAVITY 

PARIETAL  LAYER  OF  PERITONEUM 

KIDNEY  AND  ITS  RENAL  VESSELS 


The  aorta 

FIG.  167. — SHOWING  PARTIAL  AND  COMPLETE  INVESTMENT  OF  ORGANS  BY  PERITONEUM. 

lymphatics  that  scavenger  the  organ.  The  organ  has  only  one  place  where  it  is 
accessible — only  one  communication  with  the  wall. 

Examine  the  cadaver,  take  up  a  portion  of  the  small  intestine,  find  the 
superior  mesenteric  artery,  and  trace  it  down  between  its  two  parts  of  the  peritoneal 
folds.  Now,  with  your  forceps,  make  a  rent  in  one  side  of  the  mesentery,  examine, 
and  find  an  artery,  a  vein,  nerves,  glands,  and  fat,  as  represented  in  figure  166. 

4.   Explain  implantation  of  meso-structures. 

That  part  of  the  alimentary  canal  which  remained  in  its  original  mid-line  of 
the  body — as  the  greater  part  of  the  small  intestine  and  rectum — may  be  said  to 
be  an  example  of  primitive  implantation  ;  those  parts  which  contracted  adhesions 


PARIETAL  LAYER  OF  PERITONEUM 


PERITONEAL  CAVITY 


The.  aorta 

FIG.  168. — SHOWING  RETRO-PERITONEAL  LOCALITY. 


to  localities  other  than  the  mid-line,  may  be  said  to  be  examples  of  acquired 
implantation.      The  colon  and  duodenum  are  examples  of  this  latter  variety. 

5.  From  ivliat  source  does  the  peritoneum  derive  its  blood-supply  f 

It  will  be  presently  seen  that  the  abdominal  aorta  has  parietal  branches  and  vis- 
ceral branches.  The  parietal  branches,  as  the  lumbar  and  phrenics,  supply  the  peri- 
toneum covering  these  walls  ;  the  visceral  branches  supply  the  peritoneum  cover- 
ing the  organs.  Peritoneal  arteries  are,  then,  of  two  classes — visceral  and  parietal. 

6.  Explain  peritonea!  investment  of  organs. 


240 


PRACTICAL   ANATOMY. 


This  is  as  follows  :  (i)  Organs  may  simply  be  behind  the  peritoneum,  as  arte- 
ries and  veins,  in  which  case  we  say  they  are  covered  by  this  membrane.  (Fig. 
1 68.)  They  have  not  grown  sufficiently  in  thickness  to  produce  any  appreciable 
displacement  of  the  peritoneum.  Figure  168  shows  the  aorta  behind  the  peri- 
toneum, but  producing  no  bulging  forward  of  the  peritoneum.  (2)  Organs  may 
produce  appreciable  bulging  forward,  as  in  figure  167,  when  we  say  they  a  im- 
partially invested.  Now  examine  the  kidney  and  you  will  find  its  relation  to  the 
peritoneum  represented  in  figure  167  in  the  two  organs  on  the  two  sides. 

7.    What  determines  the  degree  of  peritoneal  investment  f 

The  height  to  which  any  organ  grows  determines  this.  The  peritoneum 
pushed  ahead  of  the  organ  is  called  the  mesentery  of  the  organ  and  the  peritoneal 
investment.  Mesenteries  may  be  long  or  short.  The  height  to  which  an  organ 


PARIETAL  LAYER  OF  PERITONEUM 


The  aorta 

FIG.  169. 
In  this  figure  an  organ  has  grown  to  a  considerable  height  and  a  long  mesentery  is  the  result. 


PARIETAL  PERITONEUM 
VISCERAL  PERITONEUM 


The  aorta 
FIG.  170. 

In  this  figure,  a  is  an  organ  completely  invested  by  peritoneum.  Its  mesentery  grows  high  and  falls  on  />, 
an  organ  partially  invested  by  peritoneum.  At  the  contact  point  of  a  and  b  loss  of  epithelium  occurs. 
Parts  of  organs,  or  entire  organs,  which  once  possessed  peritoneal  investment,  but  subsequently  lost 
the  same  in  this  manner,  are  said  to  be  retro-peritoneal,  or  to  have  no  peritoneal  investment.  An 
example  is  to  be  seen  in  the  case  of  the  right  kidney,  where  the  duodenum  and  colon  bear  the  above 
relation  (Fig.  170)  to  the  anterior  surface  of  this  organ. 

grows  determines,  then,  both  the  degree  of  investment  and   the   length  of  the 
mesentery. 

8.  H&W  arc  the  abdominal  muscles  classified? 

As  vertical  and  horizontal.  The  pyramidalis  and  rectus  abdominis  are  ver- 
tical ;  the  external  and  internal  oblique  and  the  transversalis  are  horizontal. 

9.  Xamc  the  abdominal  -iccak  points  in  tlic  trails   of  tlic  abdominal  cavity  and 
give  their  practical  importance  in  surgery. 

(i)  The  inguinal  canal,  limited  internally  by  the  internal  abdominal  ring,  and 
externally  by  the  external  abdominal  ring.  This  canal  lodges  the  spermatic  cord 
of  the  male  and  the  round  uterine  ligament  of  the  female.  It  is  the  succession 
of  weak  points  that  formed  the  line  of  least  resistance  to  the  descending  testicle. 


ABDOMEN.  241 

This  canal  acquires  surgical  importance  in  inguinal  hernia,  of  which  there  are  two 
arbitrary  divisions — direct  and  oblique  :  the  former  being  internal  to,  the  latter 
being  external  to,  the  deep  epigastric  artery. 

(2)  The  femoral  canal,  being  that  part  of  the  initial  three-quarters  of  an  inch 
of  the  femoral  sheath  unoccupied  by  the  femoral  vessels.     (Fig.  165.)     Normally, 
the  canal  is  occupied  by  a  fatty  connective  tissue,  with  or  without  a  lymphatic  gland. 
The  entire  amount  of  this  connective  tissue — called  technically  the  septum  crurale, 
or  septum  femorale — weighs  three  grains.    The  surgical  importance  of  this  septum 
is  due  to  the  fact  that  it  is  inferred  to  form  one  of  the  coverings  of  a  femoral  hernia. 
Just  why  rational  medical  literature  should  continue  to  dignify  this  frail  structure, 
and  place  it  in  the  same  category  with  such  structures  as  Gimbernat's  and  Pou- 
part's  ligaments,  the  femoral  sheath,  and  the  skin  itself,  is  difficult  to  determine. 

(3)  The  umbilicus  is  the  point  where  the  two  hypogastric  branches  of  the  inter- 
nal iliac  arteries  and  the  umbilical  vein  came  together  to  form  the  umbilical  cord, 
a  foetal  arrangement  that  took  impure   blood  to  the  placenta  and  returned  in  its 
stead  the  same  blood  plus  O  and  minus  CO2. 

10.   Where  is  the  spermatic  cord  made  up  and  of  what  structures  does  it  consist  ? 

It  is  made  up  at  the  internal  abdominal  ring,  to  the  outer  side  of  the  deep 
epigastric  artery,  by  the  coming  together  of  the  spermatic  artery,  the  spermatic 
veins,  the  deferential  artery,  and  the  excretory  duct  of  the  testicle — the  vas 


PARIETAL  PERITONEUM 


VISCERAL  PERITONEUM 

MESENTERIC  MARGIN 
CAVITY  OF  PERITONEUM 
MESENTERIC  STALK 

MESENTERIC  ROOT 


The  aorta 

FIG.  171. — SHOWING  SIMPLE  VISCERAL  AND  PARIETAL  LAYERS  OF  PERITONEUM  WITH  CAVITY 

BETWEEN  THEM. 

deferens.  These  structures  are  loosely  bound  together  by  connective  tissue.  In 
practical  dissection  the  cord  is  found  below  and  external  to  the  pubic  spine,  not 
as  a  cord,  but  as  a  flattened  band.  The  cord  lies  on  the  shelved  inner  and  upper 
part  of  Poupart's  ligament,  in  the  inguinal  canal.  The  function  of  the  spermatic 
artery  is  to  supply  the  testicle  with  blood,  from  which  the  testicle  secretes  semen. 
The  spermatic  veins  return  the  blood  to  the  general  circulation,  the  right  being 
tributary  to  the  ascending  vena  cava,  the  left  to  the  left  renal  vein.  The  vas  is 
the  conduit  that  leads  the  semen  to  the  vesiculae  seminales  at  the  base  of  the 
bladder.  The  artery  of  the  vas  nourishes  this  conduit  and  inosculates  with  the 
spermatic  artery. 

1 1 .  Tell  all  you  can  about  tJie  femoral  sheath. 

It  is  composed  of  two  fasciae  that  come  down  out  of  the  abdominal  cavity, 
one  in  front  of  and  the  other  behind  the  femoral  vessels.  These  fasciae  surround 
the  vessels  and  take  the  name  "femoral  sheath." 

1 2.  What  are  the  fascia  t/iat  form  the  femoral  sheath  and  why  are  they  so 
called? 

The  one  in  front  of  the  femoral  vessels  is  the  transversalis  ;  the  one  behind  the 
vessels,  the  iliac  fascia.  They  are  named  in  accordance  with  the  rule  governing  the 
naming  of  deep  fasciae — i.  c.,  according,  in  this  case,  to  the  name  of  the  muscles. 


24 2  PRACTICAL  ANATOMY. 

13.  Do  the  lumbar  arteries  assist  in  furnishing  the  peritoneum  with  blood  / 
Yes  ;  the  same  arteries  that  supply  the  walls,  supply  the  peritoneum  cover- 
ing the  walls. 

14.  What  can  you  say  of  the  lumbar  arteries  f 

They  are  four  in  number  on  each  side.  They  are  analogous  to  the  intercos- 
tal arteries.  They  arise  from  the  abdominal  aorta.  The  right  are  longer  than 
the  left  lumbar  arteries.  These  arteries  are  small  when  compared  to  their  homo- 
logues,  the  intercostals.  The  lumbar  arteries  lie  behind  the  abdominal  sympa- 
thetic chain.  According  to  their  distribution,  the  lumbar  arteries  are  classified 
as  dorsal  branches  and  abdominal  branches.  Each  has  specific  relations  and 
course.  The  dorsal  branches  pass  out  between  the  transverse  processes  of  the 
lumbar  vertebrae,  with  the  posterior  primary  divisions  of  the  lumbar  nerves,  and 
attended  by  their  corresponding  lumbar  veins,  to  be  distributed  to  the  spinal 
cord,  passing  through  the  intervertebral  foramina;  to  the  muscles  and  skin  of  the 
back  ;  and  to  the  lumbar  vertebrae  in  this  region.  The  abdominal  branches  of  the 
lumbar  arteries  pass  behind  the  sympathetic  chain  and  behind  the  quadratus  lum- 
borum  muscle.  They  are  distributed  to  the  quadratus  lumborum  and  psoas 
magnus  muscles  and  to  the  abdominal  walls. 

I  5 .    What  can  you  say  of  the  anastomosis  of  the  lumbar  arteries  / 
The  dorsal  branches  anastomose  with  each  other  and  with  the  intercostals. 
The  abdominal  branches  of  the  lumbar  arteries  anastomose  :     (i)  Above  with  the 
lower  intercostal  arteries ;  (2)  below  with  the  ilio-lumbar  and  circumflex  iliac  ; 
(3)  in  front  with  the  epigastric  and  internal  mammary. 

1 6.  If  the  abdominal  aorta  were  ligated  just  above  the  bifurcation,  how  could 
the  blood  reach  the  loiuer  extremities  ? 

Through  two  channels:  (i)  The  epigastro-mammary  arch  ;  (2)  the  lumbo- 
circumflex  anastomotic  arch. 

17.  Describe  the  epigastro-mammary  anastomotic  arch. 

An  arch  formed  by  anastomosis  between  the  deep  epigastric  artery,  a  branch 
of  the  external  iliac,  and  the  internal  mammary  artery — a  branch  of  the  subclavian. 
This  union  occurs  in  the  rectus  abdominis  muscle. 

1 8.  Describe  the  lumbo-circumflcx  anastomotic  arch. 

It  is  an  arch  formed  by  anastomosis  between  the  lumbar  arteries,  branches 
the  abdominal  aorta,  and  the  deep  internal  circumflex  iliac  artery — a  branch  of  th< 
external  iliac. 

The  arteria  sacra  media  is  the  sacral  representative  of  the  lumbar  arteries.  It 
is  to  the  aorta  what  the  coccyx  is  to  the  vertebral  column,  what  the  ensiform  car- 
tilage is  to  the  sternum — the  exhaustion.  It  is  the  representative  of  the  caudal 
artery  of  some  animals.  Its  small  branches  are  distributed  in  the  same  manner 
as  those  of  the  lumbar  region. 

19.  What  can  you  say  of  the  lumbar  veins  f 

They  accompany  the  lumbar  arteries  arid  are  tributary  to  the  ascending  \vn; 
cava. 

20.  How  would  you  explain  the  nerve-supply  of  the  peritoneum  / 

The  same  nerves  that  supply  muscles  that  enclose  a  serous  cavity  supplj 
the  serous  membrane  enclosed.  This  principle  was  pointed  out  by  Hilton  am 
Van  der  Kolk.  The  full  law,  as  given  previously,  applies  not  only  to  serous 
but  to  mucous  membranes  as  well. 

21.  What  are  the  functions  of  peritoneum  f 

It  secretes  serum  for  lubrication  of  opposed  surfaces.      It  is  a  highly  absorp- 
tive structure.       It  forms  ligaments  for   holding   organs  in  place.      It  protect 
organs  against  violence.      It  gives  strength  to  organs  which  it  invests.      It  con 
serves  heat  and  piwrnts  sudden  changes  of  temperature. 

22.  Is  serum  ever  secreted  in  abnormally  large  quantities  f 


ABDOMEN. 


243 


Yes,  and  the  terms  by  which  such  conditions  are  designated  are  hydro-pericar- 
dium, hydro-thorax,  hydro-cephalus,  and  hydro-peritoneum. 

23.  What  is  a  peritoneal  cavity  f 

The  space  between  the  visceral  and  parietal  layers  ot  the  peritoneum.  The 
same  is  true  of  any  serous  cavity — viz.,  it  is  the  space  between  a  visceral  and  a 
parietal  layer  of  serous  membrane. 

24.  What  do  we  understand  by  mesenteric  contents  ? 

All  the  structures  between  the  two  surfaces  or  folds  of  the  mesentery — /.  e. , 
in  the  mesenteric  space.  The  intestine  is,  of  course,  the  largest  structure.  (Fig. 
1 66.)  The  vessels,  nerves,  and  glands  to  and  from  the  intestine  are  all  called 
mesenteric.  They  are  all  embedded  in  a  variable  amount  of  mesenteric  fat. 
Sometimes  this  fat  is  so  abundant  as  to  completely  hide  the  vessels  from  view  ;  at 
other  times  the  vessels  may  be  seen. 

2  5 .  Explain  tlic  primitive  alimentary  canal. 

In  figure  172  you  have  a  view  of  the  primitive  canal  and  its  mesentery 
in  longitudinal  section.  Will  you  remember  that  the  mesentery  has  two  layers 


fade.  U< 
gast.Jiefiat:  omcnt 


I/MES. 


FIG.   172. — DIAGRAM  OF  THE  PRIMITIVE  ALIMENTARY  CANAL. 


with  the  arteries,  that  make  the  canal  grow,  between  them  ?  You  see  in  the  figure 
only  one  surface  of  the  mesentery.  At  an  early  period  there  is  only  one  gut  and 
one  mesentery.  This  gut  is  straight,  and  located  in  the  mid-line  and  on  the  pos- 
terior abdominal  wall.  The  gut  grows  in  proportion  to  the  blood-supply  it  receives. 
In  figure  172  this  primitive  mesentery  had  three  important  organs  between  its 
two  layers:  (i)  The  stomach,  in  the  middle;  (2)  the  liver,  between  the  two 
layers,  in  front  of  the  stomach  ;  (3)  the  spleen,  between  the  two  layers,  behind  the 
stomach. 

We  see  parts  of  this  primitive  partition  unoccupied  (i)  in  front  of  the  liver; 
(2)  between  the  liver  and  stomach  ;  (3)  between  the  stomach  and  spleen ;  (4) 
between  the  spleen  and  posterior  wall. 

26.  Can  ive  find  evidence  in  our  dissection  of  the  unoccupied  parts  just  referred  to  ? 
Yes  ;  the  one  in  front  of  the  liver  is  the  broad  or  falciform  ligament  of  the 

liver.  The  one  between  the  liver  and  stomach  is  the  gastro- hepatic  or  lesser 
omentum.  The  one  between  the  stomach  and  spleen  is  the  gastro-splcnic  omentum. 

27.  Give  the  difference  between  omentum  and  mesentery. 


244 


PR  A  CT1CAL    A  XA  TO.  MY. 


In  reality  there  is  no  difference  except  an  arbitrary  one.  Each  is  of  peri- 
toneal origin  ;  each  has  two  layers  ;  each  escorts  vessels  and  nerves  to  organs. 
Omenta  connect  organ  to  organ  ;  mesenteries  connect  organ  to  wall. 

28.  Usage  arbitrary. 

The  broad  ligament  holds  the  liver  to  the  diaphragm  ;  the  broad  ligament  ot 
the  uterus  holds  the  uterus  to  the  lateral  pelvic  walls  and  floor.  They  are  the 
mesenteries  of  these  viscera.  Usage,  however,  restricts  the  use  of  the  word  mesen- 
tery exclusively  to  the  intestines.  As  you  will  see,  the  ascending  colon  lost  its 
mesentery.  The  descending  colon  lost  its  mesentery,  except  the  rectum,  in  part, 
and  the  sigmoid.  The  transverse  colon  retained  its  mesentery. 

29.  Define  mesentcric  attachment — primitive  and  acquired. 

By  primitive  attachment  of  the  mesentery  we  mean  attachment  in  the  mid- 
line,  or  nearly  in  the  original  line  of  the  straight  gut.  The  mesentery  of  the  small 
intestine  is,  for  practical  purposes,  art  example  of  primitive  attachment ;  the  rectum 
is  primitive  in  attachment.  The  duodenum,  stomach,  and  colon  have  acquired 
attachments. 


aastro-liejiat.  oment. 


FIG.  173. — DIAGRAMS  SHOWING  (A)  THE  FORMATION  OF  THE  GREAT  OMENTUM,  AND  (£)  THE 

TION   OF   THE   INTESTINAL   CANAL. 


- 


30. 
cance  ? 


What  is  differentiation  of  the  alimentary  canal  and  its  physiological  signifi- 

In  the  evolution  of  the  alimentary  canal,  differentiation  is  the  process  whereby 
the  primitive  straight  gut  undergoes  a  change  which  determines  large  and  small 
intestines.  The  ileo-caecal  junction  is  the  place  where  this  change  took  place. 
(Fig.  172.)  The  physiological  significance  seems  to  be  simply  a  physiological 
division  of  labor,  whereby  the  small  intestine  is  specialized  for  digestive  purpose -s, 
the  large  intestine  for  disinfecting,  deodorizing,  storage,  and  extrusive  purposes. 

3 1 .    Wliat  is  rotation  .' 

It  is  the  process  by  which  the  upper  border  of  the  small  intestine  (Fig.  173) 
is  turned  from  you,  from  left  to  right,  and  brought  out  toward  you  under  the 
arch  of  the  transverse  colon  (Fig.  173),  so  as  to  be,  when  completely  turned,  as 
tr.Mire  173.  In  figure  172  both  large  and  small  intestines  have  a  common  con- 
tinuous mesentery,  as  you  see.  In  figure  173  they  still  have  the  same  mesen- 
tery, with  this  difference  :  that  for  the  small  intestine  is  twisted  on  itself  one-half 
around.  The  pivot  about  which  this  rotation  took  place  is  seen  in  figure  172— 
the  superior  mesenteric  artery.  Kxaminc  figure  172  and  sec  the  jejunum.  Trace 
this  down  to  the  caecum. 


ABDOMEN.  245 

This  is  an  explanation  of  the  fact  you  can  demonstrate  on  the  cadaver  :  that 
the  small  intestine  is  almost  completely  surrounded  by  the  ascending  transverse 
and  descending  parts  of  the  colon.  Show  this  on  your  work. 

32.  Formation  of  greater  and  lesser  peritoneal  cavities. 

In  figure  172  you  have  the  primitive  peritoneal  partition  dividing  the  abdom- 
inal cavity  into  a  right  and  a  left  half.  In  front  of  the  stomach  you  see  the  gastro- 
hepatic  omentum ;  behind  the  stomach  the  mesentery,  which  now  takes  the 
specific  name  meso-gaster.  You  see  the  initial  end  of  the  small  intestine  (duo- 
denum), and  below  this  the  remainder  of  the  small  intestine  and  all  the  large  intes- 
tine, attached  by  a  common  mesentery  ;  that  peritonium,  however,  which  corres- 
ponds to  the  colon  is  called  meso-colon,  and  that  which  corresponds  to  the  small 
intestine  is  called  mesentery.  Can  you  now  distinguish  the  three  meso-structures  ? 
Can  you  remember  that  each  has  two  layers,  between  which  are  located  the  mesen- 
teric  arteries  and  other  contents  ?  Can  you  remember  that  the  attached  margin 
of  this  meso-gut  now  extends  from  the  floor  of  the  pelvis  to  the  diaphragm,  in 
the  mid-line  ?  Can  you  remember  that  the  intestinal  margin  of  the  meso-gut 
must  become  longer,  in  proportion  to  the  growth  of  the  intestine,  large  and 
small  ?  Now  you  are  on  the  left  of  this  partition.  Thus  far  the  space  on  the  right 
is  as  great  as  that  on  the  left.  The  arrow  in  figure  173  is  represented  as  simply 
coming  through  an  artificial  opening,  to  aid  you  in  remembering  the  space  on  the 
other  side  of  the  partition.  Now  imagine  you  took  hold  of  the  partition,  the 
meso-gaster,  and  pulled  toward  you  in  the  direction  of  the  dotted  line.  Would 
you  not,  by  continued  pulling,  produce  a  bagging-out  on  your  side  of  the  parti- 
tion, and  a  consequent  depression  or  bagging-in  on  the  other  side  ?  Can  you 
imagine,  now,  if  you  pulled  long  enough,  the  beginning  of  the  depression  or  sac 
on  the  other  side  must  become  smaller  and  smaller?  The  hole  on  the  other  side 
would  admit  you  to  this  little  sac  thus  formed  by  your  pulling.  In  anatomy  the 
name  of  this  hole  is  the  foramen  of  Winslow.  It 'leads  to  the  sac  you  have  just 
formed.  This  sac  is  the  lesser  cavity  of  the  peritoneum  ;  all  the  space  outside 
of  this  is  the  greater  cavity  of  the  peritoneum. 

33.  What  parts  of  the  abdominal  viscera,  in  the  adult,  have  lost  their  peritoneal 
covering  by  pressure  atrophy,  as  referred  to  in  a  preceding  paragrapJi  / 

No  two  cases  are  exactly  alike  in  this  regard.  Still,  the  following  represents 
a  general  average,  as  you  will  meet  these  cases  in  the  dissecting-room  :  (i)  The 
posterior  part  of  the  descending  colon  rests  on  the  posterior  wall  of  the  abdomen, 
consequently  there  is  adhesion,  with  loss  of  the  specific  epithelial  element.  (2)  The 
ascending  colon,  the  second  and  third  parts  of  the  duodenum,  the  colic  and 
duodenal  elbows  to  be  presently  explained,  rest  on  the  peritoneum,  partially  in- 
vesting the  right  kidney,  and  here  is  peritoneal  loss.  The  second  part  of  the 
rectum  is  adherent  to  the  anterior  surface  of  the  sacrum,  and  here  is  peritoneal 
loss.  Each  case  is  a  law  unto  itself,  in  a  measure  ;  but  the  student  with  an  ink- 
ling of  the  developmental  principles,  as  given  in  the  foregoing,  and  as  elaborated 
in  Morris,  can  soon  acquire  a  facility  in  locating  on  his  dissections,  those  peri- 
toneal ruins,  whose  presence  forms  one  of  the  mainstays  for  the  receptacular  part 
of  the  alimentary  canal,  whose  absence  belongs  to  the  rarest  of  rare  developmental 
freaks. 

34.  Does  rotation  occur  in  every  case  ? 

Faulty  rotation,  and  even  failure  to  rotate,  may  occur.  One  interesting  case, 
found  recently  by  the  author,  showed  the  caecum  and  the  entire  colon  on  the  left 
side,  the  small  intestine  in  or  near  the  right  iliac  fossa. 

35.  Are  any  special  organs  developed  from  the  alimentary  canal .' 

The  liver  and  pancreas  are  developed  from  the  duodenum  ;  the  former  grows 
into  the  mesentery  in  front  of  the  stomach,  the  latter  into  the  posterior  meso-gaster. 
You  will  see  their  ducts  open  in  common  into  the  second  part  of  the  duodenum. 


246  PRACTICAL  ANATOMY. 


SHORT  SUMMARY  OF  PERITONEAL  CONSIDERATIONS. 

1.  The  complex  adult  alimentary  canal  and  its  complex  peritoneal   invest- 
ing membrane  are  evolved  from  a  simple  straight  gut  and  a  simple  straight  mes- 
entery. 

2.  The  abdominal  part  of  this  canal  in  the  foetus  extends  from  the  diaphragm 
to  the  anus  on  the  posterior  wall  of  the  abdominal  cavity  in  front  of  the  vertebral 
column.      It  is  attached  to  the  anterior  wall,  as  far  downward  as  the  umbilicus, 
under  the  name  of  ventral  mesentery. 

3.  The  stomach  appears  as  an  enlargement  in  the  canal,  and  its  dorsal  mesen- 
tery is  called  meso-gaster. 

4.  The  upper  part  grows  much  more  rapidly  than  the  lower,  receiving  a  more 
liberal  blood-supply.     In  round  numbers,  the  small  intestine  is  the  product  of  the 
superior  mesenteric  artery  ;  the  large  intestine  is  the  product  of  the  inferior. 

5.  At  an  early  period  the  liver  is  in  front  of  the  stomach  and  the  pancreas 
behind.     The  liver  grows  into  the  ventral  mesentery,  the  pancreas  into  the  pos- 
terior meso-gastrium.     The  primary  mesentery  of  the  pancreas  fuses  with  the 
posterior  body  wall. 

6.  As  the  liver  and  spleen  become  larger,  and  as  the  bowel  begins  to  rotate 
about  the  superior  mesenteric  artery,  the  stomach  assumes  a  transverse  position, 
the  anterior  border  becomes  the    lesser  curve,  posterior   border  becomes  the 
greater  curve,  the  left  surface  becomes  the  anterior,  and  the  right  surface  becomes 
the  posterior. 

7.  The  small  intestine  rotates  from  left  to  right  in  such  a  way  that  the  large 
intestine  extends  from   right  to  left  and  crosses  the  small    intestine  near  the 
stomach. 

8.  Rotation  accounts  for  the  duodenum  passing  under  the  second  or  trans- 
verse stage  of  the  colon  and  apparently  through  its  transverse  meso-colon. 

9.  The  meso-gaster  becomes  the  greater  omentum,  consists  of  four  layers, 
grows  out  from  the  greater  curvature  of  the  stomach. 

10.  The  duodenum   and  ascending  and  descending  colon  lose  their  mesen- 
teries. 


ABDOMINAL  CONTENTS. 

Cut  slightly  to  the  left  of  the  umbilicus,  then  through  the  linea  alba  to  the 
ensiform  cartilage.  It  may  be  necessary  to  divide  the  cartilages  of  the  two  or 
three  lower  true  ribs  to  make  ample  room.  Make  the  following  observations 
before  any  further  dissecting  is  done  : 

1.  Find  the   broad   ligament  of  the   liver  in   the  longitudinal   fissure  of  this 
organ.     See  the  round  ligament  of  the   liver  in  the  free  margin  of  the  broad. 
This  is  the  remains  of  the   umbilical  vein  that  brought  aerated  blood  from  the 
placenta  during  intrauterine  life. 

2.  Locate   the   stomach,  I  her,  spleen,  and  transverse  colon.      Lift   the   lower 
margin  of  the   liver  upward,  and  at  the  same  time  pull  the  stomach  downward  ; 
now  see  the  peritoneal  connection  between  the  liver  and  stomach — the  gastro- 
hcpatic  omentum  or  lesser  amentum.      Notice  the  peritoneal  connection  between 
the  stomach  and  the  colon.     This  is  the  Castro-colic  omentum  or  great  omentum. 
See  the  peritoneal  connection  between  the  left  end  of  the  stomach  and  the  spleen. 
This  is  the  Castro-splenic  omentum.      Folds  of  peritoneum  that  connect  organ  to 

are  called  omenta,  and  the  three  above  given  are  the  omcnta. 


Abdominal  aorta 


LEFT  CRUS  OF  DIAPHRAGM 

ISOPHAGEAL  BRANCH 


RIGHT  CRUS  Of  DIAPHRAGM 


Cystic  artery 

Sight  phrenic  artery 

HEPATIC  DUCT 

CYSTIC  DUCT 

Splenic  artery 

COMMON  BILE  DUCT 

Pyloric  artery 

Gastro-duodenal  artery 


Superior  pancreatico- 
duodenal  artery 
HEAD  OF  PANCREAS 

Inferior  pancreatico- 
duodenal  artery 

Right  gastro-epiploic 
artery 


Left  gastro-epiploic  artery 


FIG.  174. — THE  CCELIAC  ARTERY  AND  ITS  BRANCHES. 


BLADDER 


GREAT  OMENTUM 


SMALL  INTESTINE 


FIG.   175. — THE  VISCERA  AS  SEEN  ON  FULLY  OPENING  THE  AIJDOMEN  WITHOUT   DISARRANGEMENT 

OF  THE  INTERNAL  PARTS.     (After  Sarazin.) 

247 


248  PRACTICAL  ANATOMY. 

3.  Three  Divisions  of  tlie  Colon. — The  divisions  of  the  colon  are  ascending, 
transverse,  descending,  sigmoid,  and  rectum.     The  ascending  colon  extends  from 
the  right  iliac  fossa  to  the  hepatic  flexure.     The  transverse  colon  extends  from 
the  hepatic  flexure  to  the  lower  margin  of  the  spleen — the  splenic  flexure.      The 
descending  colon  extends  from  the  splenic  flexure  to  the  brim  of  the  pelvis. 

Notice  the  manner  in  which  the  three  parts  of  the  colon  are  held  in  place. 
The  meso-colon  of  the  transverse  is  quite  long ;  that  of  the  ascending  and 
descending  is  very  short;  in  fact,  the  nature  of  the  union  is  one  of  adhesion 
rather  than  mesenteric,  in  the  two  latter.  Folds  of  peritoneum  that  bind  organs 
to  walls  are  called  mesenteries.  The  continuation  of  the  descending  colon  below 
the  pelvic  brim,  to  a  point  opposite  the  second  piece  of  the  sacrum,  is  called  the 
sigmoid.  Lift  it  up  and  see  the  great  length  of  its  mesentery — called  meso- 
sigmoid. 

4.  Differential   Diagnosis  Between  Large  ami    Small    Intestine. — Inflate  the 
large  intestine  (Fig.  175)  and  see  the  following  differential  points  possessed  by 
large  intestine  but  not  possessed  by  small  intestine  :  (i)  Fatty  masses.    (2)  Longi- 
tudinal muscular  bands,  three  in  number,  and  at  equal  distances  from  each  other. 
Each  will  lead  to  the  appendix.   (3)  Sacculations,  produced  by  contraction  exerted 
by  the  longitudinal  bands. 

5-  Jejunum,  Ileum,  and  their  Mesentery. — Compare  your  dissection  with  fig- 
ure 175  and  you  will  observe  that  the  three  parts  of  the  colon  almost  surround 
the  large  central  mass  of  small  intestine.  Collect  this  mass  in  your  hands  and 
find  the  upper  end  of  the  jejunum  going  through  the  transverse  meso-colon  oppo- 
site the  third  and  fourth  lumbar  vertebra  to  become  duodenum  ;  the  lower  end 
you  will  find  near  the  right  iliac  fossa,  ending  in  the  caecum,  forming  therewith  a 
junction  called  the  ileo-caecal  junction.  Lift  the  whole  mass  of  small  intestine 
upward,  to  estimate  the  length  of  the  mesentery. 

6.  The  Duodenum. — Turn  the  transverse  colon  and  great  omentum  upward. 
Find  the  beginning  of  the  jejunum  and  shut  the  same  off  the  intestine  below 
this  point  by  a  ligature.     Now  inflate  the  alimentary  canal  above  this  point — /.  i\, 
duodenum  and  stomach.     You  will  now  see  the  transverse  part  of  the  duodenum 
passing  behind  the  superior  mesenteric  artery  and  vein. 

7.  Ciecum  and  Appendix. — You  will  find  the  caecum,  as  a  rule,  in  the  righ 
iliac  fossa.      Its  meso-caecum  may  be  long  in  one  case  and  short  in  another. 
The  longitudinal  bands  traced  downward  will  lead  to  the  appendix.     This  organ 
has  a  peritoneal   ligament — the  meso-appendix.      It  may  occupy  a  variety  of 
locations.      It  may  hang  down  in  the  pelvis  across  the  brim.      Its  usual  posi 
tion  is  in  an  angle  between  the  ileum  and  the  pelvic  side  of  the  caecum. 


A   general   review  will  now  be  made  of  what  you  have  examined  ///  situ  an 
studied  in  the  normal  position  without  cutting. 

1.  You  saw,  on  opening  the  abdomen,  the  walls  and  also  the  viscera  (organs), 
covered  by  a  very  thin,  smooth,  and  glistening    membrane — peritoneum.     The 
layer  covering  the  walls  above,  below,  in  front,  behind,  and   on    the    sides   is 
called    parietal  peritoneum  ;     that    covering    the    organs    themselves    is    called 
•visceral  peritoneum.      The  space  between  these  t\\<>  layers  is  the  peritoneal  cavity, 
which   contains  only  a  small  amount  of  serum  f<>r  lubrication.      Henceforth  you 
will   define  a  peritoneal    cavity  as  a  space  between  a  visivr.il  and  a  parietal  laye 
of  peritoneum.     (Fig.  171.) 

2.  On  the  interior  of  the  abdominal  walls  you  saw,  through  the  thin   parirta 


; 


ABDOMEN. 


249 


peritoneum,  the  urachus  in  the  mid-line  extending  from  the  summit  of  bladder  to 
the  umbilicus.  This  is  the  foetal  remains  of  the  stalk  of  theallantois  ;  it  is  covered 
by  peritoneum,  and  the  particular  name  given  the  ridge  or  fold  in  this  peritoneum 
is  plica  urachi.  This  opening  sometimes  fails  to  close. 

3.  You  saw  on  each  side  of  the  plica  urachi  the  foetal  remains  of  the  hypo- 
gastric  arteries  ;    these   are   covered   by  peritoneum,   called  plica  hypogastrica. 
The  triangular  depression  between  these   two  plicae  just  noticed  is  the  internal 
inguinal  fossa,  and  is  associated  with  direct  inguinal  hernia. 

4.  You  located  the  deep  epigastric  artery  and  veins.    To  the  inner  side  of  this 


THYROID 


LUNG 


LIVER 
Suspensory  ligament 


SMALL  INTESTINE 


BLADDER 


LUNG 

RIGHT  AURICLE 


RIGHT  VENTRICLE 


STOMACH 


PART  OF  TRANSVERSE 
COLON 


Hypogastric  artery 


FIG.  176. — THE  VISCERA  OF  THE  FCETUS.     (Rudinger.) 

artery  you  saw  the  middle  inguinal  fossa,  associated  with  direct  inguinal  hernia ; 
to  the  outer  side  the  external  inguinal  fossa,  associated  (i)  with  the  beginning  of 
the  spermatic  cord  ;  (2)  with  indirect  or  oblique  inguinal  hernia.  You  saw  also 
that  this  deep,  epigastric  artery  forms  the  outer  boundary  of  Hesselbach's  tri- 
angle. 

5.   You  saw  the  femoral  sheath,  containing  the  femoral  artery,  vein,  and  femoral 
canal.      These  structures  you  saw  leaving  the  pelvis  below  Poupart's  ligament. 
The  peritoneal  depression  corresponding  to  the  beginning  of  the  femoral  canal— 
the  femoral  ring — is  the  femoral  fossa,  and  is  associated  with  femoral  hernia. 
17 


250  PRACTICAL  ANATOMY. 

6.  Tlie  round  ligament  of  t/ie  liver,   you   will   remember,   extends  from  the 
umbilicus  to  the  liver.      It  is  in  the  free  border  of  the  broad  ligament  of  the  liver. 
It  is  the  foetal  remains  of  the  umbilical  vein.     (Fig.  176.)     You   will  remember 
that  in  the  child  before  birth,  the  placenta  purifies  the  blood,  as  do  the  lungs, 
after  birth.     The  blood  is*  taken  in  an  impure  state  to  the  placenta  by  the  hypogas- 
tric  arteries,  and  returned  pure  by  the  umbilical  vein.      (Fig.  155.) 

7.  Three  onienta  are  the  gastro-hepatic,  or  small  ;  the  gastro-colic,  or  great ; 
the  gastro-splenic.      You  learned  to  define  omentum  as  peritoneal  folds  connect- 
ing organ  to  organ.      In  your  dissection  you  saw  the  great  omentum  as  a  heavy, 
fatty  veil,  covering  in  all  the  small  intestine,  and  hanging  down  even  into  the  true 
pelvis.    This  may  even  become  a  hernia, — an  omentoccle, — and  appear  at  any  one 
of  the  four  fossae  described  in  the  foregoing  review. 

8.  The  Colon  and  Its  Subdivisions  (Fig.  175). — The  point  where  differentiation 
takes  place  is  usually  in  the  right  iliac  fossa  ;   still,  it  may  occur  above  this  point. 
You  will   see  on  your  work  two  flexures  in  the  colon — the  hepatic,  at  the  lower 
margin  of  the  right  lobe  of  the  liver  ;   the  splenic,  at  the  lower  margin   of   the 
spleen.     The  transverse  colon  lies  between  these  two  flexures.     The  descending 
colon  is  below  the  splenic  ;  the  ascending,  below  the  hepatic  flexure. 

9.  You  will  examine  and  recall  the  nature  of  the  colic  attachments.     That  of 
the  ascending,  and  also   of  the  descending,  is  in  the  nature  of  one  structure 
adherent  to  another ;  their  meso-colons,  in  other  words,  are  short ;   hence  you 
are   not  able  to  move  them  freely  from  place  to  place,  as  you  can  move  the 
transverse  colon.      On  the  other  hand,  the  meso-colon  of  the  transverse  colon  is 
very  long,  due  to   which  fact  the  transverse  is  the  most  movable  part  of  the 
colon.      Also  recall  the  definition  for  mesentery  :    peritoneal  folds  binding  organ 
to  wall.     The  meso-sigmoid  is  also  long. 

10.  Diagnostic  of  large  intestine,  you  will  remember,  are  the  three  longitudinal 
muscular  bands  of  fibres  ;    the  consequent  sacculations  produced  by  these  ;    the 
fatty  masses  called  appendices  epiploicce.     The  latter  are  variable  in  size  ;  in  one 
case  they  may  be  very  large,  in  another  quite  small  ;   they  are  always  present 
on  large  intestine.     Any  one  of  the  three  bands  will  lead  to  the  appendix. 

1 1.  As  you  will  remember,  you  inflated  the  duodenum  and  studied  the  third 
part  of  this  organ   as  it  passed  behind  the  superior  mesenteric  vessels.     The 
remaining  part  of  the  small  intestine  is  arbitrarily  divided  into  an  upper  two-fifths, 
called  jejunum,  and  a  lower  three-fifths,  called  ileum.     Jejunum  means  empty  or 
hungry,  and   ileum   means   coiled.      There  is   no  practical  histological  difference 
between  the  two.    They  are  held  by  their  mesentery  to  a  line  extending  from  the 
left  side  of  the  body  of  the  second  lumbar  vertebra,   to  the  right  sacro-iliac 
synchondrosis.     In  its  course  it  lies  upon,  as  you  will   presently  see,  the  aorta, 
vena  cava  inferior,  transverse  part  of  the  duodenum,  and  vertebral  column.      Yoi 
will  see,  then,  that  the  mesentery  of  the  small  intestine  forms  a  partition  betuvrn 
the  right  iliac  fossa  and  the  true  pelvis;  that   fluid  to  the  left  of  this  partitioi 
would  be  directed  into  the  pelvis,  to  the  right  of  the  same,  into   the  right  iliac 
fossa.      Make  this  experiment. 


You  will  now,  by  dissection,  analyze  the  following  localities  and  structim  s 

1.  The  foramen  of  Winslow. 

2.  The  root-structures  of  the  livrr. 

3.  The  K-ssiT  cavity  of  the  peritoneum. 

4.  The  inv.ikT  cavity  of  tin-  pi-ntoiu-um. 

5.  The  ascriiding,  descending,  and  transverse  duodenum. 


ABDOMEN.  251 

6.  The  pancreas  and  splenic  artery. 

7.  The  stomach  and  gastric  artery. 

8.  The  liver,  hepatic  artery,  and  portal  vein. 

9.  The  superior  and  inferior  mesenteric  arteries  and  veins. 

10.  The  anterior  relations  of  the  right  kidney. 

1 1.  The  anterior  relations  of  the  left  kidney. 

1 2.  The  root  structures  of  the  kidney. 

13.  Descriptive  renal  terms. 

The  foramen  of  Winslow  is  the  communicating  passage  between  the  greater 
and  lesser  peritoneal  cavities.  The  foramen  has  definite  boundaries,  which  must 
be  located  by  each  student,  and  then  learned.  Surgical  operations  on  the  gall 
ducts  of  late  years  have  made  it  imperative  for  the  student  of  anatomy  to  have 
such  a  thorough  knowledge  of  structures  in  this  locality,  that  by  the  sense  of 
touch  alone,  he  may  know  perfectly  both  his  longitude  and  latitude.  The 
foramen  is  variable  in  shape  ;  it  may  be  round,  semilunar,  or  triangular.  As  a 
rule,  it  will  admit  two  fingers.  Introduce  your  left  index  finger  and  find,  in  front 
of  your  finger,  the  front  boundary — the  free  border  of  the  lesser  omentum 
containing  the  hepatic  root -structures ;  behind,  the  posterior  boundary — the 
ascending  vena  cava  and  a  ligamentous  band  of  peritoneum  extending  from  the 


BALL  BLADDER 


Hepatic  artery 


Portal  vein 

FIG.  177. — RELATION  OF  STRUCTURKS  AT  AND  BELOW  THE  TRANSVERSE  FISSURE.     (Thane.) 

liver  to  the  right  kidney  ;  above  your  finger,  the  caudate  lobe  of  the  liver;  and 
below,  you  will  recognize  the  hepatic  artery  and  the  duodenum. 

The  Root-structures  of  the  Liver  (Fig.  174). — Insert  your  finger  into  the 
foramen  of  Winslow,  and  with  your  forceps  plow  through  the  anterior  layer  of 
the  gastro-hepatic  omentum.  You  will  now  find  three  large  structures,  which  a 
few  moves  of  the  forceps  will  liberate  from  their  bed  of  connective  tissue  :  (i)  To 
the  right  side  and  below,  and  corresponding  to  the  gall-bladder,  the  common  bile 
duct ;  (2)  to  the  left  side  and  above,  the  hepatic  artery ;  (3)  between  these  two, 
but  on  a  deeper  plane,  the  portal  vein.  (Fig.  177.)  Carefully  examine  the  artery 
and  you  will  find  numerous  nerves  surrounding  the  same.  They  come  from  the 
pneumogastric  and  sympathetic.  The  connective  tissue  embedding  these  struc- 
tures and  escorting  them  to  the  interior  of  the  liver  is  the  capsule  of  Glisson. 

The  Bile  Ducts  (Fig.  174). — These  are  three  in  number.  The  hepatic  brings 
bile  from  the  liver  ;  the  cystic  is  the  duct  between  the  gall-bladder  and  the  point 
where  the  hepatic  meets  it.  The  common  duct  begins  at  this  point,  passes 
behind  the  first  part  of  the  duodenum,  and  under  the  head  of-  the  pancreas,  to 
reach  the  retiring  duodenal  elbow,  where,  with  the  pancreatic  duct,  you  will 
find  it  opening  into  the  duodenum.  This  duct  is  about  four  inches  long. 

The  Hepatic  Artery  (Fig.  174). — Trace  this  vessel  to  the  cceliac  axis.  It 
lies,  as  you  will  see,  between  the  two  layers  of  the  lesser  omentum.  Follow  its 


252  PRACTICAL  ANATOMY. 

cystic  artery  to  the  gall-bladder  ;  its  pyloric  branch  to  meet  the  gastric  ;  its 
superior  pancreatico-duodenal  branch  downward  behind  the  duodenum  ;  here  one 
branch  follows  the  second  part  of  the  duodenum  and  anastomoses  with  the 
inferior  pancreatico-duodenal  branch  of  the  superior  mesenteric  artery  ;  the  other 
follows  the  greater  curvature  of  the  stomach  and,  under  the  name  of  right  gastro- 
epiploica,  anastomoses  with  the  left  gastro-epiploica,  a  branch  of  the  splenic 
artery.  Finally,  trace  the  main  branch  of  the  hepatic  artery  to  the  transverse 
fissure  of  the  liver. 

The  portal  vein  lies  between  the  common  duct  and  the  hepatic  artery.  (Fig. 
177.)  It  is  formed  by  veins  from  the  abdominal  organs  of  digestion.  Its  blood  is 
laden  with  bile,  glycogen,  and  urea.  The  bile  is  stored  up  in  the  gall-bladder  ; 
the  glycogen  is  stored  up  in  the  liver;  the  urea  is  thrown  off.  Find  the  hepatic 
veins  discharging  into  the  ascending  vena  cava,  as  this  vessel  passes  through  the 
diaphragm. 

The  hepatic  veins  take  all  blood  from  the  liver  brought  to  that  organ  by 
the  hepatic  artery  and  portal  vein.  The  vein  discharges  into  the  ascending  vena 
cava,  just  as  that  vessel  is  passing  through  the  diaphragm. 

The  Greater  and  Lesser  Peritoneal  Cavities. — A  knowledge  of  these  cavi- 
ties must  be  gained  by  study  of  the  evolution  of  the  peritoneum  and  alimentary 
canal,  from  a  straight  gut  and  single  simple  mesentery.  (See  Morris.)  The 
foramen  of  Winslow  connects  all  the  cavity  you  can  see  thus  far,  with  the  lesser 
cavity,  behind  the  stomach.  By  mechanical  devices  your  teacher  will  demon- 
strate the  modus  operandi  of  rotation,  and  this  demonstration  will  interpret  the 
description  given  in  the  larger  text.  Permit  me  to  add  in  this  place  that  every 
organ,  with  all  its  adnexa,  grows  up  behind  peritoneum,  pushes  this  ahead  of 
itself,  and  thereby  becomes  invested  by  the  same,  partially  or  completely.' 

To  Dissect  the  Duodenum. — Thoroughly  inflate  the  stomach  and  duodenum, 
as  previously  directed.  Then  divide  the  gastro-colic  omentum  and  turn  the 
transverse  colon  down  toward  the  pelvis.  Lift  the  stomach  up,  and  observe  the 
lesser  cavity  of  the  peritoneum  behind  the  same.  In  cutting  the  great  omentum, 
care  must  be  taken  not  to  injure  the  arteries  along  the  greater  curve  of  the 
stomach.  (Fig.  174.)  Now  remove  the  colon  from  the  second  stage  of  the  duo- 
denum. The  stages  of  the  duodenum  are  :  (i)  From  the  pylorus  of  the  stomach 
to  the  gall-bladder,  two  inches  ;  (2)  from  the  gall-bladder  to  the  hilum  of  the 
kidney,  three  inches;  (3)  from  the  hilum  of  the  kidney  to  the  duodeno-jejunal 
angle,  five  inches.  These  stages  are  called  ascending,  descending,  and  tram 
verse,  respectively. 

Relations  of  Transverse  Duodenum. — You  will  find,  above,  the  superk 
mesenteric  vessels  and*the  head  of  the  pancreas;    in  front,  the  superior  mesei 
teric  vessels,  the  mesentery,  and  small  intestine.      Behind  you  will  now  dissec 
down  with  the  forceps,  and  find  the  aorta,  vena  cava  inferior,  the  crura  of  the 
diaphragm,  and  the  fourth  lumbar  vertebra.     On  the  left,  the  transverse  duode- 
num terminates  in  the  jejunum  ;  on  the  right,  in  the  descending  duodenum, 
the  middle  one-third  of  the  kidney. 

The  Pancreas  and  Splenic  Artery. — A  very  careful  dissection  of  the  pan- 
creas must  be  made.  The  organ  is  delicate.  It  lies  behind  the  stomach  (Fig.  180) 
hence  turn  the  stomach  up  to  expose  the  same.  Steps  :  (i)  Locate  the  splenic 
artery  by  gently  lifting  the  upper  border  of  the  pancreas.  Follow  the  artery  to 
the  spleen.  You  will  now  find  it  necessary  to  divide  the  Castro-splenic  omentum, 
but  in  cloin;4  this  do  not  injure  the  arteries  !  Notice  and  save  the  pancreatic 
arteries,  large  and  small,  given  to  this  organ — the  pancreas — by  the  splenic  artery. 
Trace  out  the  branches  given  to  the  stomach.  Find  the  gastro-epiploica  sinistra 
artery.  (2)  Now  dissect  out  the  head  of  the  pancreas.  Trace  the  superior  pan- 
creatico-duodenal artery  between  the  pancreas  and  the  duodenum,  taking  notk 


ABDOMEN.  253 

of  branches  to  each.      Find  the  excretory  duct  of  this  organ — the  pancreatic  duct 
— opening  into  the  duodenum  with  the  common  bile  duct. 

The  Stomach  (Fig.  174). — This  organ  has  an  cesophagcal  opening  ;  a 
pyloric  opening  ;  an  anterior  surface,  on  which  you  will  find  anastomosing  the 
transverse  arteries  from  the  gastric  artery  and  the  right  and  left  gastro-epiploic 
arteries  ;  a  posterior  surface,  likewise  occupied  by  arteries  ;  a  greater  curvature, 
occupied  by  the  greater  omentum  ;  a  lesser  curvature,  occupied  by  the  lesser 
omentum  ;  &fundus,  in  relation  with  the  spleen  by  the  gastro-splenic  omentum. 
Now  trace  the  gastric  artery  from  the  coeliac  axis  to  the  gastro-oesophageal  junc- 
tion ;  here  you  will  see  the  artery  divide  into  two  branches — one  to  the  walls  of  the 
oesophagus,  the  other  to  the  cardiac  end  of  the  stomach.  The  main  artery 
follows  the  lesser  curve  of  the  stomach  and  anastomoses  with  the  pyloric  branch 
of  the  hepatic  artery. 

The  liver  must  be  studied  and  dissected  with  reference  to  : 

1.  Lobes  and  their  visceral  impressions. 

2.  Fissures  and  their  occupants. 

3.  Ligaments  and  their  derivation. 

4.  Capsule  of  Glisson  and  its  function. 

5.  Blood-  and  nerve-supply. 

6.  Fcetal  remnants  and  their  location. 

7.  The  portal  vein  and  its  formation. 

8.  The  hepatic  veins  and  their  escape. 

9.  The  gall-bladder  and  bile  ducts. 

10.  The  descriptive  terms  used. 

1 1.  The  relations  to  other  structures. 

Lobes. — (i)  Right  lateral;  (2)  left  lateral;  (3)  quadrate;  (4)  caudate;  (5) 
Spigelian. 

Impressions  are  produced  by  continuous  contact  with  certain  adjacent  organs. 
On  the  under  or  visceral  surface  find:  (i)  the  renal  impression  ;  (2)  the  colic 
impression  ;  (3)  the  duodenal  impression  ;  (4)  the  gastric  impression. 

Fissures. — (i)  The  transverse  fissure  is  the  most  important.  It  transmits  the 
hepatic  artery,  the  portal  vein,  the  hepatic  ducts,  and  the  hepatic  branches  of  the 
vagus  and  sympathetic  nerves.  In  front  of  it  is  the  quadrate  lobe  ;  behind  it  the 
caudate  and  Spigelian  lobes.  (2)  The  left  longitudinal.  This  separates  the  left 
from  the  right  lobes,  and  has  an  anterior  and  a  posterior  part.  The  anterior  part 
contains  the  round  ligament ;  the  posterior  part  contains  the  remains  of  the  ductus 
venosus.  (3)  The  fissure  for  the  gall-bladder  and  (4)  the  fissure  for  the  ascending 
vena  cava.  Note,  too,  and  show  on  your  dissection,  that  on  the  posterior  sur- 
face of  the  liver  are  found  two  fissures  already  mentioned — (a)  fissure  for  the 
ductus  venosus,  (b}  fissure  for  the  vena  cava  ;  while  on  the  inferior  or  visceral 
surface  are  found  three  fissures — (a)  transverse,  (b}  umbilical  for  round  liga- 
ment, (c)  vesicle  for  the  gall-bladder.  (5)  The  right  longitudinal.  This  also 
consists  of  an  anterior  branch  that  contains  the  gall-bladder  and  a  posterior 
branch  that  contains  the  vena  cava.  The  two  are  interrupted  by  the  caudate 
lobe.  Compare  your  dissection  with  figure  178. 

The  letter  H  includes  the  five  fissures  of  the  liver  in  this  manner  :  the  trans- 
verse fissure  forms  the  cross-bar  ;  the  fissure  for  gall-bladder  and  fissure  for  vena 
cava  form  one  vertical  bar ;  the  fissure  for  the  ductus  venosus  and  the  fissure  for 
the  round  ligament  form  the  other  vertical  bar. 

The  hepatic  ligaments  are  five  in  number.  One  of  these  is  a.  false  liga- 
ment, a  foetal  remnant  called  the  round  ligament,  the  ligamentum  teres  hepatis. 
It  occupies  the  anterior  part  of  the  left  longitudinal  fissure.  The  other  four  liga- 
ments are  of  peritoneal  origin,  and  are  called  :  (i)  The  suspensory,  broad,  or  falci- 
form ;  (2)  the  right  lateral  ;  (3)  the  left  lateral ;  (4)  the  coronary.  The  latter 


254 


PRACTICAL    ANATOMY. 


binds,  as  you  will  see,  the  posterior  surface  of  the  liver  to  the  diaphragm.  The 
lateral  ligaments,  which  you  will  see  on  lifting  the  extremities  of  the  liver,  are 
simply  outward  prolongations  of  the  coronary  ligament.  The  liver  is  firmly 
fused  with  the  diaphragm,  a  perfect  appreciation  of  which  you  can  only  gain 
from  study  of  the  embryology  of  the  alimentary  canal. 


Vena  cava 


BILE  DUCT 
Portal  ve; 
ffe.patic  artery 
SPIGELIAN  LOBE 


UMBILICAL  FISSURE 
FIG.   178. — THE  INFERIOR  SURFACE  OF  THE  LIVKR. 


LEFT  LOBE 


Vena  cava 


SPIGELIAN  LOBE 


FIG.  179. — POSTERIOR  SURFACE  OF  Tin    I.ivi  u. 


Glisson's  Capsule. — You  will   recall  your  dissection  of  the  root-structui 
of  the  liver.      Yon  fouml  the  hepatic  artery  dividing  into  two  branches,  the  portal 
vein  the  same,  and   two  hepatic  ilncts  coming   down  to  join  the  cystic;  you  saw 
nerves  which  are   called    hepatic  branches   from   tin-  vagus  and  sympathetic,  sur 
rounding   the    hepatic    artery.      Now   recall    this:   the   very   intimate  manner   r 


al 

- 


ABDOMEN.  255 

which  these  structures  were  bound  together  by  connective  tissue.  This  connec- 
tive tissue  is  the  capsule  of  Glisson — the  framework  for  the  hepatic  root-struc- 
tures. 

Hepatic  Nerves  and  Arteries. — The  nerves  reach  the  liver  through  the 
transverse  fissure,  are  protected  in  transit  by  the  capsule  of  Glisson,  are  dis- 
tributed to  the  substance  of  the  liver  on  the  branches  of  the  portal  vein  and 
hepatic  artery.  These  nerves  come  from  the  hepatic  plexus,  one  of  the  divi- 
sions of  the  coeliac  plexus.  This  plexus  is  made  up  of  branches  from  the 
sympathetic,  the  right  phrenic,  and  the  left  pneumogastric  or  vagus  nerve.  The 
nutrient  artery  to  the  liver  is  the  hepatic.  The  liver  receives  blood  for  purifica- 
tion from  all  the  other  abdominal  organs  of  digestion,  through  the  portal  vein  ; 
all  the  blood  in  the  liver  escapes  by  the  hepatic  veins  into  the  vena  cava.  To  find 
these  veins,  turn  the  liver  clown  into  its  normal  position,  locate  the  emergence  of 
the  vena  cava  from  the  abdominal  cavity  through  the  diaphragm,  and  into  the 
pericardium.  Now  cut  through  the  diaphragm  at  this  point  and  plow  through 
liver  substance,  and  you  will  find  the  hepatic  veins.  Another  method  is  this  : 
having  located  the  vena  cava  above  the  diaphragm,  cut  a  hole  in  its  walls  and 
follow  the  vessel  downward  until  you  see  its  hepatic  tributaries. 

Foetal  Remains. — These  are  the  round  ligament  and  the  ductus  venosus. 
The  former  is  the  connective-tissue  remnant  of  the  umbilical  vein,  that  in  the 
foetus  brought  pure  blood  from  the  placenta.  (Fig.  155.)  This  vein,  on  reaching 
the  liver,  broke  up  into  three  channels  :  (i)  The  greater  part  of  the  blood 
joined  the  portal  vein  and  traversed  the  liver  ;  (2)  a  small  amount  entered  the 
left  lobe  ;  (3)  a  small  quantity  passed  through  a  vessel — the  ductus  venosus — to 
meet  the  left  hepatic  vein,  as  that  vessel  was  entering  the  vena  cava.  After  the 
lungs  became  the  organ  of  respiration,  the  placental  circulation  lost  its  specific 
character  as  a  conduit,  t  The  main  vessel,  the  umbilical  vein,  dwindled  to  a  mere 
cord — the  round  ligament.  The  three  termini  of  the  vein  did  the  same,  and  are 
known  as  remnants.  The  ductus  venosus  dwindled,  and  is  consequently  in  the 
adult  a  fcetal  remnant. 

The  portal  vein  in  its  relation  to  the  root-structures  of  the  liver  will  be  seen 
in  figure  177.  In  your  dissection  you  have  found  it  embedded  in  Glisson's  cap- 
sule, and  occupying  a  place  between  the  hepatic  artery  and  common  bile  duct, 
and  posterior  to  both.  Its  tributaries  come  from  all  the  organs  in  the  abdominal 
cavity  associated,  with  the  digestion  of  food,  except  the  liver.  The  veins  which 
you  must  demonstrate  on  your  dissection  as  forming  the  portal  vein  are  :  (i)  The 
superior  mesenteric  ;  (2)  the  inferior  mesenteric  ;  (3)  the  splenic  ;  (4)  the 
gastric.  Notice  particularly  on  your  dissection  that  three  veins — the  gastric, 
splenic,  and  superior  mesenteric — come  together  to  form  the  portal  vein  directly  ; 
the  inferior  mesenteric  is  tributary  to  the  splenic,  hence  it  is  not  a  primary,  but  a 
secondary  tributary  to  the  portal  vein. 

The  hepatic  veins  must  be  located  according  to  the  two  methods  given  under 
caption  of  Hepatic  Nerves  and  Arteries.  (Page  253.)  Having  found  the  hepatic 
vein,  look  on  its  under  surface  for  "the  remains  of  the  ductus  venosus,  for,  you 
will  remember,  one  branch  of  the  umbilical  vein  in  the  foetus  terminated  here. 

(Fig.  I55-) 

The  gall-bladder  and  its  system  of  ducts  must  now  be  carefully  dissected. 
Any  degree  of  rough  manipulation  will  defeat  a  perfect  dissection.  Follow  these 
steps  :  (i)  Take  the  organ  in  the  left  hand,  and  with  your  forceps  in  your  right 
carefully  dissect  the  connective  tissue,  holding  the  gall-bladder  in  the  cystic 
fissure.  (2)  Having  now  liberated  the  organ  from  its  bed,  and  having  exercised 
every  care  not  to  injure  the  vessels  and  ducts  attached  thereto,  you  may  (3)  cut 
a  slit  in  the  fundus  of  the  organ,  introduce  a  blowpipe,  and  inflate.  (4)  Have  an 
assistant  ligate  as  you  inflate.  (5)  Now  follow  downward,  and  liberate  from  the 


256  PRACTICAL  ANATOMY. 

capsule  of  Glisson  the  ducts  :  hepatic  (two),  cystic,  and   common.      Follow  this 
latter,  the  common  bile  duct,  three  and  one-half  inches  to  its  confluence  with  the 
pancreatic  duct,  in  the  receding  angle  of  the  duodenum. 
The  descriptive  terms  used  in  speaking  of  the  liver  are  : 

1.  The  root,  transverse  fissure,  or  porta  hepatis.     This  is  where  the  vessels, 
nerves,  and  ducts  enter,  surrounded  by  the  capsule  of  Glisson. 

2.  T/ie  superior  or  phrenic  surface  is  in  relation  to  the  inferior  surface  of  the 
diaphragm.     It  is  covered  by  peritoneum,  except  a  small  space  between  the  two 
layers  of  the  suspensory  ligament. 

3.  The  inferior  or  visceral  surface  rests    on   the   stomach,  duodenum,  colic 
elbow,  right  kidney.     Two  places  are  not  covered  by  peritoneum  :  the  fissure  in 
which  the  gall-bladder  rests  and  the  transverse  fissure.      Surgically,  this  is  the 
most  important  part  of  the  liver,  and  should  be  most  faithfully  studied  by  the 
student. 

4.  The  posterior  surface  is  a  territory  you  can  see  only  when  you  remove  the 
liver.      It  is  mostly  uncovered  by  peritoneum,  and  is  limited  by  the  anterior  and 
posterior  layers  of  the  coronary  ligament. 

5.  Tlie  anterior  border  is  the  one  interrogated  in  physical  examinations  of  the 
liver.      It  is  quite  thin  and  is  marked  by  two  notches,  one  for  the  suspensory  liga- 
ment and  one  for  the  fundus  of  the  gall-bladder.     This  latter  is,  in  health,  oppo- 
site the  ninth  costal  cartilage.     This  border  is  about  in  line  with  the  ribs. 

6.  The  extremities,  right  and  left,  are  associated  with  the  lateral  ligaments,  but 
have  no  special  importance  in  physical  diagnosis.   The  hepatic  elbow — a  coinage*— 
will  be  explained  when  the  anterior  relations  of  the  right  kidney  are  considered. 

7.  Peritoneal  investment  of  the  liver  is  for  practical  purposes  complete  ;  never- 
theless, on  each  surface  we  have  found  areas  not  completely  covered.     This  has 
been  explained  under  the  head  of  peritoneum  on  page  238. 

The  relation  of  the   liver  to    other  organs  is  one  of  the   most  fascinating 
and  instructive  parts  of  the  work  thus  far  encountered,      (i)   Now  show  on  your 
dissection  that  the  superior  surface  of  the  liver  is  related  to  the  under  surface  of 
the  diaphragm,  and  separated  by  the  diaphragm  from  the  bases  of  the  lungs,  base 
of  the  pericardium,  anterior  abdominal  wall,  and  six  or  seven  lower  ribs  on  the 
right  side.     (2)  Show  that  the  inferior  surface  of  the  liver  lies  on  the  right  kidney 
and  its  adrenal ;  on  the  hepatic  flexure  of  the  colon  ;   on  the  descending  duode- 
num ;   on  the  gall-bladder  and  its  duct ;   on  the  root-structures  of  the  liver;  or 
the  right  end  of  the  stomach  ;   on  the  upper  curve  of  the   duodenum  ;  on  th< 
anterior  surface  and  lesser  curve  of  the  stomach  ;  on  the  lesser  omentum. 
Show  that  posteriorly  the  liver  is  in  relation  with  the  diaphragm  and  its  crui 
the  tenth  and  eleventh  thoracic  vertebrae  and  their  ribs,  the  oesophagus,  aorta, 
vena  cava,  and  thoracic   duct.     To  show  these  posterior  relations  separate  the 
liver  from  the  diaphragm  and  pull  it  far  forward,  but  do  not  injure  the  vena  cava 
you  may  ligate  and  then  cut  the  hepatic  veins.     This  will  give  you  an  opportu- 
nity to  study  the  coronary  ligament  also.     All  the  above  relations  are  to  be  studied 
without  cutting  anything  except  possibly  the  hepatic  vein,  as  above  indicated. 

The  Superior  Mesenteric  Artery. — To  make  a  good  dissection  of  this 
artery  and  its  branches,  turn  the  transverse  colon  up  and  pull  the  mass  of  small 
intestine  forming  the  jejunum  and  ileum  far  down  over  the  left  iliac  region,  as 
shown  in  figure  180.  Now,  remember  the  mesentery  contains,  between  its  two 
layers,  all  the  vessels,  glands,  nerves,  and  lymphatics  that  go  to  or  come  from 
the  small  intestine.  Remember  all  those  struetmvs  arc  embedded  in  connective 
tissue,  just  as  are  the  root-structures  of  the  liver  enclosed  by  Glisson's  capsule 
that  the  function  of  this  mesenteric  connective  tissue  is,  like  Glisson's  capsult 
protective  and  supportive-,  and  contains,  in  some  persons,  large  quantities  ot  I. it 
technically  designated  mesenteric  fat. 


ABDOMEN. 


257 


Dissection. — Locate  the  main  stems  of  the  artery  and  vein  as  they  emerge 
from  the  under  border  of  the  pancreas,  gently  thrust  your  forceps — never  the 
scalpel — through  the  upper  layer  of.  the  mesentery,  then  use  your  fingers  instead 
of  the  forceps  and  you  can  easily  strip  off  the  remainder  of  the  peritoneum  out 
to  the  intestinal  margin  of  the  mesentery.  Trace  out  with  your  forceps,  by 
removing  the  mesenteric  connective  tissue,  always  in  the  direction  of  the  vessel, 
the  following  branches:  (i)  The  ileocolic  branch  to  the  appendix,  caecum, 
ascending  colon,  and  ileum  ;  (2)  the  right  colic  artery  to  the  ascending  colon  ; 
(3)  the  middle  colic  artery  to  the  transverse  colon  ;  (4)  the  main  bulk  of  the 
artery  to  the  jejunum  and  ileum  under  the  name  of  intestinal  branches  or  vasa 


Left  colic  artery 

Superior  mesen- 
teric artery  and 
vein 


Ileo-colic  artery 


VERMIFORM 
APPENDiX 


Vasa  intestini 
tennis 


SMALL  INTESTINES 


FIG.   180. — THE  SUPERIOR  MKSENTERIC  ARTERY  AND  VEIN. 
(The  colon  is  turned  up,  and  the  small  intestines  are  drawn  over  to  the  left  side.) 


intestini  tenuis  ;  (5)  a  small  branch  already  found — the  inferior  pancreatico- 
duodenalis.  The  veins  must  be  dissected  at  the  same  time.  If  now  you  will 
thoroughly  wash  the  mesenteric  fat  away  with  ether,  and  permit  the  specimen  to 
dry,  the  sympathetic  nerves  accompanying  the  arteries  may  be  seen. 

The  Inferior  Mesenteric  Artery. — To  dissect  this  artery  and  its  accompany- 
ing vein,  take  the  mass  of  jejunum  and  ileum  far  over  to  the  right  side.  (Fig.  181.) 
Locate  the  main  stem  of  the  artery  at  its  origin  from  the  abdominal  aorta, 
make  a  hole  through  the  peritoneum,  and,  as  in  the  dissection  above  described, 
strip  off  the  peritoneum.  Now  trace  out  the  following  branches  :  (i)  The  sig- 
moid  artery  to  the  sigmoid  flexure  of  the  descending  colon  ;  (2)  the  superior 


258  PRACTICAL   ANATOMY. 

haemorrhoidal  artery  to  the  rectum  ;  (3)  the  left  colic  artery  to  the  descending 
colon. 

Summary. — (i)  The  descending  colon  and  rectum  are  supplied  with  blood 
by  the  inferior  mesenteric  artery.  The  blood  from  this  area  is  returned  by  the 
inferior  mesenteric  vein,  which  passes  behind  the  pancreas  and  is  tributary  to  the 
splenic  vein.  (2)  The  remaining  part  of  the  intestinal  canal,  below  the  stomach, 
including  the  small  intestine  and  the  ascending  and  transverse  colons,  is  supplied 
by  the  superior  mesenteric  artery.  The  blood  from  this  area  is  collected  by  veins 
which  come  together  to  form,  with  the  gastric  and  splenic  veins,  the  portal  vein. 
The  name  portal  circulation  is  given  to  the  veins  coming  from  all  the  abdominal 


Middle  colic  artery  — 


Inferior  pancreattco- 

duodenal  artery 

Superior  mesenteric 

artery 

Riyht  colic  artery 


A  bdominal  aorta  - 
Vena  cava  inferior  . 


Right  common  iliac  _ 

artery 

Middle,  sacral  artery  — 
and  vein 


I.fft  colic  artery 

JuJ'erior  inrsenleric 

1 1  in 

Inferior  mrsni/i  rir 
artery 

Left  co/ic  ttrlerii 
!iij<  rior  in  i. •ie  liter  ic 
artery 


Left  common  iliac 

i-i  in 

Sigmoid  artery 


Superior  tiii'tiiur 
r/tuiilal  tirlt-ry 


FIG.   181. — THE  INKKKIOK  MISKN  1 1  UK-  AKTKKY  AND  VKIN. 
(The  colon  is  turned  up,  and  the  small  intestines  are  drawn  to  the  right  side.) 


organs  of  digestion,  except  the  liver.  This  blood  is  laden  with  urea,  glycogen, 
and  bile,  all  of  which  are  removed  from  the  blood  in  the  li\vr. 

Anastomosis  of  Arteries  to  the  Abdominal  Organs  of  Digestion. — (i) 

Tin-  gastric  artery  from  the  cceliac  axis  supplies  the  abdominal  part  of  the  (esoph- 
agus, the  side  of  the  stomach  represented  by  the  lesser  curve,  and  anastomoses 
with  the  hepatic,  at  the  pyloric  end.  (2)  The  hepatic  artery  supplies  the  liver 
and  communicates,  through  the  Castro-duodenal  artery,  with  both  the  splenic 
and  superior  mesenteric  arteries.  (3)  The  several  branches  of  the  mesenteries 
successively  anastomose,  so  you  can  trace-  from  (esophagus  to  rectum  the  con- 
tinuous blood-supply  to  all  the  viscera  of  this  system. 

Anterior  Relations  of  the  Right  Kidney. —  The  anterior  surface  of  the 
right  kidney  is  occupied,  from  the  kidney  forward,  (i)  by  the  anterior  part  of  the 
fatty  capsule  ;  (2)  by  the  following  organs  :  liver,  duodenum,  colon.  For  the 


ABDOMEN. 


259 


purpose  of  aiding  the  memory,  call  the  visceral  relation  that  of  the  three 
elbows  :  the  hepatic  elbow,  the  duodenal  elbow,  the  colic  elbow.  Now  demon- 
strate as  follows  :  Carefully  pull  the  hepatic  flexure  of  the  colon  downward,  and 
notice  that  this  is  made  up  of  the  upper  end  of  the  ascending  and  the  proximal 
end  of  the  transverse  colon,  and  rests  approximately  on  the  lower  third  of  the 
kidney.  (Fig.  182.)  Next  trace  down  the  second  part  of  the  duodenum  (inflated), 
and  see  that  it  forms  a  flexure  where  it  joins  the  transverse  duodenum.  Turn 
this  off  and  call  it  the  duodenal  elbow,  observing  that  it  occupies  the  middle  third 
of  the  kidney.  Lastly,  observe  the  anterior  border  of  the  liver  come  down  and 
suddenly  recede  backward  and  upward.  It  covers  the  upper  third  of  the  anterior 
surface  of  the  kidney,  and  forms  the  hepatic  elbow. 

Notice,  too,  that  the  areas  occupied  by  the  duodenal  and  colic  elbows  have 
lost  their  peritoneum,  in  accordance  with  a  law  explained  under  the  head  of  peri- 
toneum. The  left  kidney  has  two  non-peritoneal  areas. 

Anterior  Relations  of  the  Left  Kidney. — The  first  relation  is  the  fatty  cap- 
sule. Then  the  following  viscera  you  will  remove  in  this  order  :  (i)  The  fundus 


DUODENAL  AREA  HEPATIC  AREA  GASTRIC  AREA 

(NON-PERITONEAL)       (NON-PERITONEAL)       CAVAL  AREA      (PERITONEAL) 


DUODENAL  AREA 
(NON-PERITONEAL)          A\ 


PANCREATIC  AREA 
(NON-PERITONEAL) 


COLIC  AREA 
(NON-PERITONEAL) 


COLIC  AREA  OF 
SPLEEN 


COLIC  AREA 
(NON-PERITONEAL) 


PERITONEAL  AREA  WITH  RIGHT 
COLIC  VESSELS 


PERITONEAL  AREA  WITH  LEFT 
COLIC  VESSELS 


FIG.   182. — DIAGRAM  SHOWING  ANTERIOR  RELATIONS  OF  KIDNEYS  AND  SUPRARENAL  BODIES. 


of  the  stomach  ;  (2)  the  tail  of  the  pancreas  ;  (3)  the  descending  colon  ;  (4) 
the  last  part  of  the  duodenum. 

Posterior  Relations  of  Each  Kidney. — Carefully  remove  the  kidney  from 
its  bed  of  fat  and  connective  tissue,  and  turn  the  same  to  the  mid-line  with  all 
its  root-structures  attached.  Great  care  must  be  taken  in  handling  the  left  one 
not  to  injure  the  left  spermatic  vein  (ovarian,  if  a  female),  which  discharges  into 
the  left  renal  vein.  Then,  having  removed  the  posterior  part  of  the  fatty  capsule, 
you  will  find  three  nerves:  (i)  The  last  thoracic;  (2)  the  ilio-hypogastric  ;  (3) 
the  ilio-lumbar.  Then  you  will  be  able  to  make  out  the  (i)  quadratus  lumborum 
muscle,  covered  by  the  anterior  lamella  of  the  lumbar  fascia;  (2)  the  diaphragm  ; 
(3)  the  psoas  magnus  muscle  ;  and  (4)  the  lowest  intercostal  artery. 

The  Root-structures  of  the  Kidney  (Fig.  183). — These  are,  from  before  back- 
ward, as  met  in  your  dissection  :  (i)  The  vein  ;  (2)  the  renal  artery  and  its  sym- 
pathetic nerves  ;  (3)  the  expansion  of  the  ureter,  known  as  the  pelvis  of  the  kid- 
ney. You  will  find  these  structures  loosely  bound  together  by  connective  tissue, 
like  the  capsule  of  Glisson  or  the  mesenteric  connective  tissue.  This  you  must 
divide  in  the  direction  of  the  structures.  You  will  now  puncture  the  ureter  in 


260 


PRACTICAL   ANATOMY. 


the  region  of  the  brim  of  the  pelvis  and  inflate  the  same  to  see  the  beauty  of  the 
pelvis  of  the  kidney. 

Descriptive  Terms. — The  kidney  has  a  superior  and  an  inferior  extremity  ;  an 
anterior  and  a  posterior  surface  ;  a  strong  fibrous  capsule,  which  may  be  easily 
peeled  off.  The  place  where  the  nerves,  vessels,  and  duct  pass  into  the  kidney 
is  called  the  hilum.  (Fig.  183.)  Cut  through  the  kidney  longitudinally,  from 
the  outer  to  the  inner  border,  and  see  the  cortical  and  pyramidal  structure  of  the 


Cystic  artwy 

HEPATIC  DUCT 

CYSTIC  DUCT 

COMMON  DUCT 

Putin/  a  i ,. 

Gastro-duodenal  br. 

Superior  pylnrii-  In 

Hepatic  arlrri 

Right  suprarenal  mY 
Inferior  tvpi-inrim' 
artery 
Renal  artery 

Renal  vein 

Inferior  vena  cava 
KIDNEY 


Right  spermatic  vei 


Right  spermatic  artery 

Quadratus  lumborum 

muscle 

Right  lumbar  artery  and 
left  lumbar  vein 
Ureteric  branch  of 
spermatic  artery 


Middle  sacral  vessels 


LEFT  LOBE  OF  LIVER 


(ESOPHAGUS 

Left  phrenic  artery 

Right  phrenic  artery 
Superior  suprarenal 
Gastric  artery 
Inferior  suprarenal 
Splenic  artery 

Left  phrenic  rein 
Left  tuprarena: 
Superior  meseiiteric 

artery 
KIDNEY 

Ureteric  branch  of  renal 
Left  spermatic  rein 


URETER 

Left  spermatic  artery 


Inferior  mesenteric  artery 


Ureteric  branch  of 
spermatic 


Ureteric  branch  of 

common  iliac 
Common  iliac  artery 


External  iliac  arle 
Internal  iliac  artery 

FIG.  183. — THE  ABDOMINAL  AORTA  AND  ITS  BRANCHKS,  WITH  TIIK  INFERIOR  VENA  CAVA  AND  ITS 

TRIBUTARIES. 


kidney.  Figure  613  (Morris)  shows  the  interior  of  the  sinus  and  the  formation  of 
the  pelvic  portion  of  the  ureter.  The  ureter  having  been  inflated,  examine  for 
one  or  more  small  urcteric  arteries,  branches  of  tin  spennatic,  superior  vesical, 
and  common  iliac  arteries  on  the  ureter.  Connected  with  the  upper  extremity 
of  the  kidney  by  connective  tissue,  find  the  adrenals  or  suprarenal  capsules.  These 
arc  ductless  glands.  Trace  out  their  arteries  to  the  renal  and  phrenic  arteries 
and  to  the  aorta. 


ABDOMEN.  261 


THE  SYMPATHETIC   NERVE. 

In  the  cranium,  neck,  thorax,  abdomen,  and  pelvis  you  will  have  to  do  with 
arteries,  nerves,  viscera,  and  localities  where  the  sympathetic  nerve,  while  perhaps 
anatomically  the  smallest  structure,  in  these  localities  is  nevertheless  the  most 
important  structure.  It  would  be  just  as  wanton  to  ignore  and  destroy,  or, 
what  is  worse,  fail  to  see,  the  hairspring  of  a  watch,  if  you  were  taking  a  watch 
to  pieces,  as  it  would  be  to  dissect  a  human  body  and  not  have  a  clear  under- 
standing of  the  sympathetic  nerve. 

The  necessity  of  at  least  familiarity  with  the  rudiments  of  this  system  of 
nerves  will  be  apparent,  when  I  remind  you  that  you  will  hear  more  or  less 
about  the  sympathetic  nerve  from  every  chair  in  your  medical  course.  The 
physiological  action  of  drugs  depends  on  vaso-contraction  and  dilatation  to  a 
great  extent.  The  rationale  of  the  obstetrician's  Crede  manipulation,  is  stimula- 
tion of  sympathetic  uterine  contraction.  The  physiologist  invokes  the  sympa- 
thetic system  when  he  would  explain  the  function  of  viscera.  The  pallors  and 
hyperaemias,  the  exanthemata,  and  the  thousand  and  one  strange  phenomena  in 
skin  diseases  are,  to  a  greater  or  less  degree,  temporarily  or  permanently  amen- 
able to  remedies  that  act  in  some  way  through  the  sympathetic.  In  general 
and  special  medicine,  in  surgery  and  all  its  special  departments,  you  will  hear  of 
parts  played  by  the  sympathetic  nerve.  Are  you,  then,  to  remain  in  ignorance,  or 
are  you  to  gain  a  comprehensive  knowledge  of  this  subject  by  intelligent  dissection  ? 

An  erroneous  opinion  prevails  among  students  that  the  sympathetic  cannot 
be  seen,  on  account  of  its  smallness.  No  ;  this  is  not  the  reason  students  often  fail 
to  find  and  become  familiar  with  these  nerves.  You  can  see  at  a  distance  of  six 
feet  the  cervical,  thoracic,  and  abdominal  ganglia,  of  the  gangliated  cord.  You 
can  see  at  a  distance  of  ten  feet  the  solar  and  cardiac  plexuses.  You  can  see  at  a 
distance  of  four  feet  the  hypogastric  plexus.  You  can  see  at  a  distance  of  two 
feet  the  communicating  branches  extending  from  one  ganglion  to  another  of  the 
gangliated  cord.  You  can  see  the  greater  and  lesser  splanchnics  five  feet  away. 
At  a  distance  of  fourteen  inches  you  can  see  the  rami  communicantes — the  little 
nerves  connecting  the  sympathetic  cord  and  the  anterior  primary  divisions  of  the 
spinal  nerves.  At  a  distance  of  twelve  inches  you  can  see  the  gastric,  hepatic, 
splenic,  and  mesenteric  sympathetic  nerves.  At  a  distance  of  ten  inches  you  can 
see  the  sympathetic  nerves  on  the  internal  carotid  artery  in  its  cavernous,  petrosal, 
or  cerebral  stages.  You  can  see  the  Vidian  nerve,  the  petrosal  nerves,  the  ophthal- 
mic ganglion.  At  the  closest  normal  visual  range  you  can  even  see  the  sympa- 
thetic nerves  that  accompany  the  ovarian  and  uterine  arteries.  You  can  even 
see  the  long  and  short  ciliary  nerves  to  the  eyeball. 

I  saw  a  man  last  summer  who  could  not  see  the  moon  through  a  Yerkes 
telescope.  In  this  case  the  moon  was  on  exhibition,  and  the  powerful  lens  was 
in  working  order,  but  the  man  in  question  did  not  know  where  to  look.  So,  in 
anatomy,  the  sympathetic  nerve  is  everywhere  on  exhibition.  Its  dimensions 
are  not  great,  it  is  true  ;  still,  if  you  know  where  to  look,  you  will  have  no  diffi- 
culty in  finding  this  nerve.  The  peculiar  sympathetic  lustre  makes  its  identity 
certain,  after  you  have  dissected  and  studied  this  nerve  a  short  time.  The  object 
of  this  chapter  is  to  teach  you  where  to  look,  to  find  the  sympathetic  nerve  in 
all  regions  of  the  body  ;  to  teach  you  how  to  let  the  nerve  alone,  having  once 
found  the  same — and  this  is  its  dissection  ;  to  furnish  you  with  an  outline, 
embracing  the  rudiments  of  what  is  known  of  the  sympathetic  to-day — and  this 
by  the  following  questions  and  their  answers  : 

I .    What  is  a  sympatJietic  nerve  ? 

Cranial  and  spinal  nerves  are  collectively  designated  somatic  nerves.     These 


262 


PRACTICAL   ANATOMY. 


preside  over  the  special  senses  and  supply  muscles  with  motion  and  skin  and 
membranes  with  sensation.  These  muscles  and  parts,  constituting  so  much  of 
the  bulk  of  the  body,  depend  on  certain  organs  for  air,  blood,  for  the  products 
of  digestion  ;  in  other  words,  there  are  certain  organs  in  the  body  concerned  in 
the  preparation  of  nutriment  for  the  tissues.  This  nutriment  must  be  distributed 


n  of  Sites 


to  G.ofRoot  ofPneumog, 
taPe-trosal  G. 
Glosso-ph. 


Vidian  to$-P  Ganglion 


to  U.ofPne  utnoycutrtc 
tofffpoyloaaal  Jff. 

to  br.  of  Ext.  Carotid.  A. 


to  Pharyngeal  P 
to  Inf.  Thyroid  A . 

Cardiac  br.fkPneumogast. 
andfiec.Laryrufeal  Kcrvr 


CarcLiac  Plexus 
.Coronary  Plexus 


G.=  GANGLION. 
P.=  PLEXUS. 
A.-ARTERY. 

1. 2.3.*.  BRAN  CHES. 
FROM  PNEUMOGASTSiC 
NERVE  TO  THE  CARDIAC 
PLEXUS. 


kpaticP.  , 
,^-f^f   Cystic 

Gaslrvjtuadenal 


4th 
from  Couyyoal 


Ganglion  Impar. 
FIG.  184.— Tin    SY> 


5  Sup.ffemorrnoidaL 
6  Spermatic  Plexus. 


Pelvic  P.  orlnfHypogastric. 

SUPPLIES  ALL  THE  PELVIC  VISCERA  AND  THE  PENIS. 


Frvm  fbttsrS  Compend  of  Anatomy. 
SYSTEM  OF  NERVES. 


to  the  tissues,  at  tinu-s  in  maximal  cuiantities,  at  other  tinu-s  in  minimal  cjuantitics. 
Tin-  action  of  the  s\-mpathetic  is,  among  other  things,  to  dilate  or  contract  the 
vessels  bearing  this  blood,  for  thr  nutrition  of  the  tissues.  In  this  sense  then 
a  feeder  of  organs,  the  sympathetic  looks  after  the  lixes  of  organs  hence  its 
synonym,  tlu-  mrve  of  organic  life. 


ABDOMEN.  263 

2.  From  where  to  where  docs  the  gangliated  cord  extend  ? 

From  the  ganglion  of  Ribes  above,  on  the  anterior  communicating  artery,  to 
the  ganglion  impar  below,  on  the  coccyx. 

3.  Hou>  many  ganglia  are  in  each  region  of  the  spine  / 

Three  in  the  cervical  ;  twelve  in  the  dorsal ;  four  in  the  lumbar  ;  four  in  the 
sacral  region. 

4.  Where  will  we  find  these  ganglia  in  the  cervical  region  in  dissection  f 

In  the  neck,  behind  the  carotid  sheath,  the  superior  cervical  ganglion  ;  on 
the  inferior  thyroid  artery,  the  middle  cervical  ganglion  ;  on  the  inner  side  of  the 
superior  intercostal  artery,  the  inferior  cervical  ganglion.  This  one  is  somewhat 
difficult  to  find,  as  it  lies  in  fatty  connective  tissue.  Look  between  the  trans- 
verse process  of  the  seventh  cervical  vertebra  and  the  neck  of  the  first  rib,  and 
you  will  find  it.  Dissolve  the  fat  in  ether  and  pack  the  region  with  a  two  per 
cent,  solution  of  formaline,  to  develop  well  the  branches  of  this  ganglion,  which 
branches  are  somewhat  numerous. 

5 .  Where  are  the  ganglia  located  in  the  thorax  ? 

You  will  find  them  in  fatty  connective  tissue,  behind  the  pleura  costalis,  on 
the  heads  of  the  rib.  These  are  smaller  than  the  cervical,  but  easily  found. 

6.  Where  will  we  find  the  ganglia  in  the  lumbar  portion  of  the  gangliated  cord  ? 
Along  the  inner  margin  of  the  psoas  magnus  muscle,  behind  the  peritoneum, 

in  fatty  connective  tissue. 

7.  Where  vvill  we  find  the  ganglia  in  the  sacral  region  of  t/te  gangliated  cord? 
Along  the  inner  side  of  the  anterior  sacral  foramina,  behind  the  peritoneum, 

in  fatty  connective  tissue. 

8 .  HcrLv  are  these  ganglia,  in  the  regions  above  mentioned,  connected  ? 

By  interganglionic  cords  or  nerves.  These  can  all  be  seen,  and  must  be 
demonstrated  on  the  cadaver  by  the  student. 

9.  What  are  the  rami  commnnicantes  ? 

They  are  two  little  nerves  that  extend  from  the  spinal  nerve,  shortly  after  its 
emergence,  to  the  ganglia  of  the  gangliated  cord.  These  are  the  somatic  com- 
munications referred  to  above. 

i  o.  How  do  sympathetic  nerves  reach  the  organs  or  parts  they  are  destined  to 
supply  ? 

In  two  general  ways  :  (i)  The  majority  of  sympathetic  nerves  travel  with 
the  artery  to  the  organ,  and  take  the  same  name  as  the  artery.  (2)  Some  few 
accompany  somatic  nerves  to  a  part ;  the  sympathetic  nerves  to  the  pharynx 
accompany  the  vagus  and  glosso-pharyngeal  nerves,  and  then  take  the  name  of 
the  part  supplied. 

1 1 .  Are  there  any  important  nerves  given  off  from  the  superior  cervical  gan- 
glion ?     If  so,  zv/iat  arc  they,  and  where  are  they  distributed  ? 

Yes  ;  from  the  ganglion  are  given  off  branches  that  accompany  the  branches 
of  the  internal  carotid  artery  to  the  brain  ;  the  ophthalmic  artery  to  the  orbit ; 
communicating  branches  to  the  third,  fourth,  fifth,  and  sixth  cranial  nerves. 

1 2.  What  branches  are  given  off  from  the  middle  cervical  ganglion  ? 
Nerves  to  all   the   branches  of  the  external  carotid  artery  ;   nerves  to  the 

pharyngeal  plexus  ;  a  nerve — the  superior  cardiac  nerve. 

13.  What  nerves  are  given  off  from  the  inferior  cervical  ganglion  f 
From  this  are  given  off  the  principal  nerves  to  the  cardiac  plexus. 

14.  Explain  the  sympathetic  distribution  from  the  twelve  thoracic  ganglia. 

In  round  numbers,  the  six  upper  are  given  to  the  cardiac  plexus  ;   the  six 
lower  to  the  solar  and  renal  plexuses,  by  the  splanchnics. 
i  5.   How  is  the  hypogastric  plexus  formed  f 

By  branches  from  the  lumbar  and  sacral  parts  of  the  gangliated  cord. 
1 6.    What  is  the  function  of  the  cardiac  prevertebral  plexus  ? 


264 


PRACTICAL   ANATOMY. 


It  supplies  lungs  and  heart.  It  is  formed  by  sympathetic  nerves,  supple- 
mented by  filaments  of  the  phrenic  and  vagus  nerves. 

17.  How  is  the  solar  plexus  formed,  and  to  what  organs  arc  its  brandies  dis- 
tributed.'' 

1    5**  Cranial  tferve 
2.  The  Orbit 

3  3rd  4^6^  Cranial  tfe 

4  To  the  Arteries  of  the  ffraiti 


to  (LofRoot  ofPneumog. 
toPttrosal  ff.of^ 
Glos.so-ph. 


7o  muscles  concerned 
in  respiration 
Cervical  Plexus 
Somatic  Pain 


To  upper  extremity 
Brachial  Plexus 
Somatic  Pain 


To  Thoracic  Walls 
6  upper  intercostals 

Somatic  Pain 


To  Abdominal  Walls 
6  lower  intercostals 

< ; 

Somatic  Pain 


Lumhar  Plexus 

To  front  ofThioh  anJ/fnet 

\ 

Somfi/ic  Pain 


Sacral  Plexus 

To  posterior  part  ofThiah 

To  Lea 

To  external  Genitals 

Somatic  Pain 


G.'GANOLION. 

Cardiac  br.  fhPn  eu-mogastric     p.  =  p  L  E  x  u  s . 
andRec.Larynytal  Rcrves        A..  ARTERY. 


G.ofWrisberg 

'Cardiac  Plexus    .  n  ^  ffgarf  ana<LunjS 


1.2.3.4.   BRAN  CHES. 
FROM    PNEUMOOASTRIC 

NERVE  TO  THE  CARDIAC 
PLEXUS. 


repaticR  . 
;  u^rf   Cystic 

Gastrculuadenal 


the  Abdominal  Oryam 


S  Sup.Hemorrfioidal. 
6  Spermatic  Plexus. 


>  To  the  Pelvic  0/yans 

Pelvicp.orlnfflypogaslnc. 

SUPPLIES  ALL  THE  PELVIC  VISCERA  AND  THE  PENIS. 


from  Couyyoal 


Ganglion  Impar. 


Fivrn'tbtterS  Compend  ofJlnatomu. 
FIG.  185. — THE  SYMPATHETIC  SYSTEM  OF  NERVES. 


By  the  sympathetic,  as  above  indicated,  in  union  with  filaments  from  the 
vagus  nerves.  It  is  distributed  to  the  abdominal  organs,  exclusive  of  the  organs 
in  the  pelvis. 

1 8.    To  what  is  tlie  liypogastric  /Vr.ivc.v  distributed  / 

To  the  organs  in  the  pelvis.     It  will  be  remembered  the  nerves  reach  organs 


ABDOMEN.  265 

by  accompanying  the  artery  to  the  part.      Hence  it   occurs   that  the  ovary  and 
testicle  receive  their  nerve-supply  from  the  renal  plexus. 

In  the  subjoined  figure  the  tendency  of  plexuses  to  supply  areas  below  their 
own  level  will  be  seen. 

19.  Wliat  is  meant  by  automatic  action  in  sympathetic  ganglia  ? 

The  ganglia  of  the  heart  and  intestine  have  the  power  of  independent  action  ; 
still,  the  sympathetic  is  no  longer  considered  a  separate  system. 

20.  Is  there  any  definite  means  of  judging  of  the  location  of  disease  founded  on 
the  nature  or  location  of  pain  ?      Or,  conversely,  may  pain  incident  to  disease  of  the 
various  organs  in  the  three  great  cavities — thorax,  abdomen,  and  pelvis — be  ration- 
ally accounted  for  in  the  distribution  of  cerebro-spinal  or  somatic  nerves  ? 

Yes  ;  for,  as  the  following  pages  will  show,  somatic  nerves  often  report  pain 
that  has  its  origin  in  an  organ  far  away  from  the  origin.  These  somatic  nerves 
also  transmit  both  pain  and  motion  more  rapidly. 

For  an  example,  in  valvular  lesion  the  pain  in  the  chest  behind  the  sternum, 
so  long  as  reported  by  the  sympathetic  nerve  to  the  patient  as  a  subjective 
symptom  of  disease,  is  constant  and  aching.  When,  however,  the  case  assumes 
a  grave  aspect,  and  the  pain  is  reported  to  the  patient's  sensibility  by  the  somatic 
nerves,  then  an  aching  pain  is  replaced  by  one  described  as  darting  and  stabbing. 
Then,  too,  the  location  of  the  pain  will  have  changed.  The  aching  sympathetic 
pain  behind  the  sternum  is  now  felt  in  the  little  and  ring  fingers.  Consult  the 
characters  of  sympathetic  and  somatic  pain  in  the  following  paragraphs.  Con- 
sult figure  185  and  see  :  (i)  The  heart  is  supplied  by  sympathetic  nerves  by  the 
cardiac  plexus  ;  (2)  the  sympathetic  nerves  forming  the  cardiac  plexus  com- 
municate with  the  somatic  nerves  in  the  area  where  are  given  off  the  nerves 
forming  the  brachial  plexus  ;  (3)  as  sensory  nerves  report  pain  peripherally, 
we  may  logically  account  for  the  digital  pain  in  valvular  lesions  in  the  distri- 
bution of  the  brachial  plexus  in  general,  or  in  the  specific  distribution  of  the 
ulnar  nerve  in  particular.  The  same  is  true  of  all  diseases  of  viscera  in  which 
pain  figures  conspicuously  as  a  subjective  symptom.  To  find  the  possible 
somatic  area  where  pain  may  occur,  use  figure  185  according  to  the  following 
steps  :  (a)  Where  is  the  diseased  organ  located  ?  (V)  Are  the  organs  in  this 
area  supplied  by  the  cardiac,  solar,  or  hypogastric  plexus  ?  (<r)  At  what  place 
do  the  sympathetic  nerves  forming  the  plexus,  supplying  the  organ  under 
consideration,  communicate  with  the  somatic  or  spinal  nerves?  (4)  What 
becomes  now  of  the  spinal  nerves  given  off  where  the  sympathetic  communicate 
with  them  ?  Do  these  spinals  form  either  the  cervical,  brachial,  lumbar,  sacral, 
or  coccygeal  plexus,  or  do  they  form  the  thoracic  nerves?  (5)  Trace  out  the 
distribution  of  the  spinal  nerve,  and  you  will  have  the  somatic  route  pursued  by 
pain  originating  in  the  sympathetic  area.  The  steps  then  would  be  :  \d]  sympa- 
thetic area  ;  ($)  communicating  branches  with  the  somatic  nerves  ;  (<:)  transfer 
centre  in  the  cord,  (d]  Somatic  distribution  of  nerves  over  which  pain  may  travel. 
Articulations  may  be  involved  in  reflex  pain.  In  the  case  of  pain  in  the  little 
finger  incident  to  valvular  lesion,  the  student  must  be  prepared  to  answer  the 
question,  Where  may  the  pain  have  been  in  this  same  valvular  lesion,  aside  from 
in  the  skin  of  the  little  finger  and  one-half  the  ring  finger  ?  (6)  The  same  nerve, 
the  ulnar,  also  sends  sensory  branches  to  every  articulation,  which  any  of  the 
muscles  supplied  by  its  motor  filaments  moved  or  assisted  in  moving  ;  hence  in 
the  elbow  or  any  of  the  following  joints  a  reflex  pain,  darting  and  stabbing  in 
character,  may  be  a  sequel  of  valvular  heart  lesions.  (7)  Distribution  of  cranial 
sympathetic  nerves  ;  (8)  Distribution  of  external  carotid  sympathetic  nerves  ; 
(9)  Distribution  of  cardiac  sympathetic  nerves;  (10)  Distribution  of  solar 
sympathetic  nerves;  (11)  Distribution  of  hypogastric  sympathetic  nerves. 
18 


266  PRACTICAL  ANATOMY. 


TRANSMISSION  OF  PAIN. 

1.  Local  in  the  organ  supplied  by  the  sympathetic. — In  this  case  the  pain  is 
a  sensation  of  heat,  fullness,  distress,  tenderness,  oppression,  burning,  weight,  and 
uneasiness. 

2.  Somatic. — In  this  case  the  pain  is  reflected  out  over  the  somatic  nerves 
nearest  to  the  sympathetic  area  supplying  the  irritated  organ.     This  is  indicated 
by  the  arrows  on  the  left.     (Fig.  185.) 

3.  The  long  arrow  indicates  transference  of  pain  from  any  of  the  visceral  areas 
through  the  gangliated  sympathetic  cord  to  the  cranial  nerves.      In  this  manner 
an  ovarian,  uterine,  intestinal,  or  cardiac  irritation  may  be  even  many  times  more 
severe  in  the  distribution  of  the  fifth  cranial  nerve  than  at  the  seat  of  disease. 
Through  the  auriculo-temporal  branches  of  the  fifth,  pain  in  the  scalp  may  be 
reported. 

ANATOMICAL  CLASSIFICATION  OF  PAIN. 

To  aidt  your  memory  and  to  teach  you  to  be  expert  in  tracing  the  transmis- 
sion routes  of  pain  from  sympathetic  system  to  somatic  system,  and  to  enable 
you  to  determine,  from  the  nature  of  the  pain,  whether  a  somatic  or  sympathetic 
region  is  involved,  learn  the  subjoined  lists  of  adjective  expressions,  and  study 
carefully  the  preceding  figure,  showing  in  a  comparative  schematic  manner  the 
respective  distribution  of  somatic  and  sympathetic  nerves. 


CHARACTER  OF  PAIN  IN  THE  SYMPATHETIC. 

As  the  sequel  will  show,  pain  in  the  sympathetic  nerve,  pure  and  simple,  is 
designated  by  writers  and  lecturers  on  medicine  by  the  following  adjective 
expressions  :  A  sensation  of  weight,  constriction,  fullness,  uneasiness,  heat,  dull- 
ness, pricking,  distress,  tenderness,  oppression,  or  burning.  To  be  more  explicit, 
the  above  terms  are  used  descriptively,  while  our  task  now  is  to  show  that  in 
those  very  diseases  where  these  terms  are  used  descriptively  we  find  a  sympa- 
thetic nerve-supply  only  involved. 


CHARACTER  OF  PAIN  IN  SOMATIC  NERVES 


^-,,-f 


Is  designated  by  the  following  adjectives  :  Cutting,  shooting,  gnawing,  dart- 
ing, tearing,  intense,  sharp,  severe,  aching,  griping,  gnawing,  boring,  and  fulgurat- 
ing.     It  is  our  task  here  to  show  that  where  such  pains  occur  a  somatic  area  i 
either  pathologically  involved  or  a  somatic  nerve  is  reporting  pain  that  originate 
in  a  sympathetic  area.      In  other  words,  the  character  of  the  pain,  as  the  sequ 
will  show,  is  a  reliable  index  to  the   nature  of  the  region   involved  by  the  pain 
producing  agent. 

TABLE  SHOWING  COMMON  DISEASES, 

THE  NATURE  OF  THEIR  PAIN,  WHEN  LOCAL,  AND  THE  NATUKK  OF  THKIK   PAIN  AND  mi 
ANATOMICAL  ROUTE  OF  ITS  TRANSMISSION,  WHEN  REFI.I  \. 

{Sympathetic  pain,  dull;  when  in  center  of  lung,  no  pain. 
Somatic  pain,  sharp  and  lancinating. 
Reflex,  lumbago  on  sound  side. 
Nerve  route,  via  cardiac  plexus  and  intercostal  nerves. 
r  Sympathetic  pain,  heavy  and  uneasy. 
p.  i   Somatic  pain,  intense,  sharp,  cutting,  lancinating. 

sy 1    Reflex,  epigastric  region,  subaxilla,  chest  wall. 

Nerve  route,  cardiac  plexus  and  intercostals. 


ABDOMEN. 


267 


Bronchitis, 


Pericarditis,     .... 


Endocarditis,      .    .    . 


Valvular  Lesions,  .    . 


Angina  Pectoris,    .    . 


Thoracic   Aneurysm, 


Renal  Colic, 


Aneurysm  of 
Thoracic  Aorta, 


Aneurysm  of  Abdom- 
inal Aorta 


Spinal  Meningitis, 


Locomotor  Ataxia,    . 


Renal  Inflammation, 


Cancer  of  Stomach,  . 


.Gastric  Ulcer,      .    .    . 


Intestinal  Colic,     . 

i 

\ 

i 

TABLE  SHOWING  COMMON  DISEASES. — (Continued?) 

r  Sympathetic  pain,  not  severe,  dull,  heavy  behind  sternum. 

j    Somatic  pain,  sharp  soreness,  acute. 

1    Reflex,  epigastrium,  short  ribs. 

v.  Nerve  route,  cardiac  plexus  via  intercostals. 

Sympathetic  pain,  distress,  in  incipiency. 
Somatic  pain,  acute,  darting,  paroxysmal. 
Reflex,  precordial  tenderness  and  pain. 
Nerve  route,  cardiac  plexus  via  intercostals. 

Sympathetic  pain,  distress  rather  than  pain. 
Somatic  pain,  acute  when  complicated  by  pericarditis. 
Reflex,  precordial  tenderness  and  pain. 
Nerve  route,  cardiac  plexus  via  intercostals. 

Sympathetic  pain,  constant  and  aching. 

Somatic  pain,  darting,  stabbing. 

Reflex,  chest,  left  shoulder,  arm,  forearm,  ringers. 

Nerve  route,  cardiac  plexus  via  circumflex,  internall  cutaneous,  ulnar. 

Sympathetic  pain,  burning  pain  under  sternum. 
Somatic  pain,  intense  and  lancinating. 
Reflex,  chest,  arm — right,  neck — lower  extremity. 
Nerve  route,  cardiac  plexus  via  somatic  system. 

Sympathetic  pain,  aching  locally. 
Somatic  pain,  intense  and  boring. 
Reflex,  back  and  chest. 
Nerve  route,  cardiac  plexus  via  intercostals. 

Sympathetic  pain,  pricking  locally. 

Somatic  pain,  severe,  excruciating. 

Reflex,  chest,  abdomen,  penis,  testicles. 

Nerve  route,  solar  plexus  via  intercostals,  internal  pudic. 

Sympathetic  pain,  local  aching  and  burning. 
Somatic  pain,  severe  and  radiating. 
Reflex,  chest  walls  and  abdomen. 
Nerve  route,  cardiac  plexus  via  intercostals. 

Sympathetic  pain,  heavy  in  back. 
Somatic  pain,  intense  in  abdominal  walls. 
Reflex,  abdominal  walls. 
Nerve  route,  solar  plexus  via  intercostals. 

Sympathetic  pain,  locally  deap-seated  and  boring. 

Somatic  pain,  severe  and  radiating. 

Reflex,  upper  and  lower  extremities. 

Nerve  route,  sympathetic  and  somatic  systems. 

Sympathetic  pain,  sympathetic  ataxia. 
Somatic  pain,  fulgurating  pain  in  extremities. 
Reflex,  girdle  pain  in  abdominal  walls. 
Nerve  route,  somatic  and  sympathetic. 

Sympathetic  pain,  dull  pain  locally. 

Somatic  pain,  severe,  lancinating. 

Reflex,  penis,  perineum,  and  testicle. 

Nerve  route,  renal  plexus  via  internal  pudic  nerves. 

Sympathetic  pain,  locally  gnawing. 

Somatic  pain,  lancinating. 

Reflex,  absent  in  eight  per  cent,  of  recorded  cases. 

Nerve  route,  solar  and  vagus. 

Sympathetic  pain,  burning  and  gnawing. 

Somatic  pain,  pain  often  absent  for  days. 

Reflex,  epigastric  tenderness. 

Nerve  route,  solar  plexus  via  intercostals. 

Sympathetic  pain,  griping. 

Somatic  pain,  severe  character. 

Reflex,  epigastrium. 

Nerve  route,  solar  plexus  via  lower  intercostal. 

Sympathetic  pain,  uneasiness. 

Somatic  pain,  tearing  and  cutting. 

Reflex,  umbilicus  and  right  iliac  regions. 

Nerve  route,  solar  plexus  via  lumbar  plexus. 


f  S 
S 


268  PRACTICAL  ANATOMY. 

TABLE  SHOWING  COMMON  DISEASES. — (Continued.} 
i    Sympathetic  pain,  dull  and  aching. 

.,   ^  ,-   .  i   Somatic  pain,  umbilical  tenderness. 

Acute  Enteritis,      .    .   -<    Reflex   .£doininal  walls 

'    Nerve  route,  solar  plexus  via  lumbar  plexus. 

{Sympathetic  pain,  local  burning. 
Somatic  pain,  gnawing. 
T"»       Q  \~  A    1_  L  J      • 

Reflex,  right  nypochondrium. 
Nerve  route,  solar  plexus  -via  intercostals. 
r  Sympathetic  pain,  local  pain  set  aside. 
Intussusception,     .    .   3   Somatic  pain,  severe  in  umbilical  region. 

i    Reflex,  abdominal  walls. 

*     V  Nerve  route,  solar  plexus  via  lower  intercostals. 
i-  Sympathetic  pain,  set  aside  locally,  or  colicky. 

Strangulated  Hernia,   \   S?omatic  P*in'  sevfre  ™.  umbilicus. 
/    Reflex,  abdominal  walls. 

v  Nerve  route,  solar  plexus  via  intercostals. 
r  Sympathetic  pain,  dull  locally. 
Parenchymatous  \   Somatic  pain,  mild  somatically. 

Hepatitis 1    Reflex,  under  right  scapula,  in  shoulder. 

v.  Nerve  route,  solar  plexus  via  circumflex  and  intercostals. 
r  Sympathetic  pain  ;  when  deep-seated,  no  pain. 
Suppurative  1   Somatic  pain,  severe  when  superficial. 

Hepatitis \   Reflex,  right  shoulder. 

v  Nerve  route,  solar  plexus  via  circumflex  nerve. 
r  Sympathetic  pain,  weight  in  right  hypochondrium. 
r-    ...  )   Somatic  pain,  very  seldom  any  pain. 

'   1   Reflex,  no  reflex. 

v.  Nerve  route,  solar  plexus  via  vagus. 

r  Sympathetic  pain,  darting  in  various  directions. 

^  r  T  -  *   Somatic  pain,  severe. 

Cancer  of  Liver,    .    .   ,   Reflex  Jg  abdominal  wa]ls 

v.  Nerve  route,  solar  plexus  via  intercostals. 
r   Sympathetic  pain,  uneasiness  and  distress.       * 
Bili-vrv  Calculi  \   Somatic  pain,  severe,  cutting,  tearing. 

'   ]   Reflex,  chest  and  abdomen. 

v.  Nerve  route,  solar  plexus  via  intercostals. 
Sympathetic  pain,  dull  and  distressing. 

Ovaritis \   Somatic  pain,  severe  and  annoying. 

Reflex,  scalp,  back,  thigh. 

Nerve  route,  hypogastnc  plexus  via  fifth  nerve,  lumbar  plexus. 


Rationale  of  reflex  pain  and  the  anatomical  factors  involved  in  a  simple 
physiological  reflex  circuit.  The  rationale  of  reflexes  is  to  be  found  in  the  law 
of  projectiles.  Pain  as  a  projectile  having  reached  a  transfer  centre,  pursues  the 
line  of  least  resistance  or  the  point  of  greatest  traction.  The  factors  involved  in 
a  reflex  circuit  are  :  (i)  A  sensory  nerve  leading  to  a  transfer  centre.  (2)  A  sen- 
sory nerve  leading  from  a  transfer  centre  to  a  sentient  area.  3.  A  transfer  centre 
communicating  centrally  with  a  sympathetic  area,  and  peripherally  with  a  somatic- 
area.  In  figure  186  the  pain  is  in  the  end  of  the  penis;  the  disease  is  renal 
colic.  The  sensory  nerve  to  the  penis,  the  internal  pudic,  a  branch  of  the  sacral 
plexus  ;  the  nerve-supply  to  the  kidney  is  from  the  renal  plexus.  The  pain  is 
more  severe  in  the  distribution  of  the  somatic  nerves  than  at  the  scat  of  th< 
disease. 

In  like  manner  figure  186  shows  the  same.  This  \vc  will  then  call  a  sen- 
sory reflex  pain,  in  which  the  pain  is  greatly  exaggerated  by  its  transmission 
over  the  somatic  part  of  the  reflex  circuit.  A  motor  reflex  pain  may  be  repre- 
sented in  figure  187.  Here  also  is  a  reflex  circuit,  the  constituents  of  which  are 
(i)  a  sensory  nerve  ;  (2)  a  motor  nerve  ;  (3)  a  transfer  centre.  The  phenomena 
produced  are  called  motor  reflexes. 

Kemembcr,  these   schematic  figures  are   introduced  here,  not  for  the  purpose 


is 

: 


ABDOMEN.  269 

of  attempting  to  teach  the  physiology  of  reflexes,  but  simply  to  impress  on  the 
student  the  imperative  necessity  of  being  able,  in  dissection,  to  show  the  place 
where  somatic  and  sympathetic  nerves  communicate,  by  the  ncrvi  comniunicantes. 

Is  there  any  difference  in  the  traiismissional  power  of  souiatie  and  sn/ipathetic 
nerves  / 

From  the  decided  difference  in  the  character  of  pain  reported  by  these  two 
nerves  we  would  conclude  there  is  a  difference. 

Wliat  is  the  difference  in  tran smissional  power  / 

This  is  conjectural  only.  Simply  to  aid  the  memory,  we  might  view  the 
subject  in  the  light  of  logical  reasoning.  For  physiological  facts,  however,  you 
must  consult  physiologists.  Structure  is  the  correlative  of  function  ;  hence, 
m.irked  differences  in  function  entail  consequent  marked  differences  in  structure. 


Renal  Plexus  „ 

y ntdney  - 

Renal  Colic 

X  &reter.  Bladder,  Lumbar  and  Penis  reflex  ar*>. 


Cardiac  Plexus 

X —  -X  Heart 


-X  Arm,  Finyers,  Shoulder  and  Abdominal  Wall* 


Cardiac  Plexus  L 

n  y 


-X- 


Pneumonia 

1  Pain  in  Lumbar  ret/ton 

2  Pain  in  the  Kpigasfrum 
.?  Pain  on  the  sound  side 


Pelvic  Plexus  ^^-  Ovaritis 

x  —  <C^ Salpinailts 

Back  ^~^^Displacements 


X  Chest 

Extremities  -  Tfie  reflex  areas  frequently 

(iastric  Plexus 
x y  Stomach 


•nd  Cancer 
X  Abdominal  Walls,  TTie  reflex  area 


ffypogastric  Plexus 

y ffites tine  - 

Enterataia 


'liacreyion  end  Umbilicus ,  The.  reflex  area 

FIG.  186. — SHOWING  SCHEMATICALLY  A  SENSORY  REFLEX  CIRCUIT. 

The  converse  is  true.  The  sympathetic  individual  fibre  is  smaller  ;  its  fibres 
undergo  numerous  interruptions,  not  only  in  the  ganglia  of  the  gangliated  cord, 
but  also  in  numerous  other  plexuses,  of  which  the  plexuses  of  Auerbach  and 
Meissner  may  be  taken  as  the  type. 

Somatic  and  sympathetic  nerves  are  routes  by  which  nerve-impressions  travel. 
Nerve-impulses,  of  whatever  kind,  are,  then,  projectiles,  and  amenable  to  the  law 
of  projectiles  :  "  Projectiles  follow  the  line  of  greatest  traction,  the  point  of 
least  resistance,  or  the  resultant  of  the  two."  If,  then,  the  small  calibre  of 
sympathetic  nerves,  and  their  frequent  interruptions,  form  a  resistance  to  nerve- 
impulses,  then  somatic  nerves,  possessing  neither  of  these  assumed  impedi- 
ments, logically  furnish  lines  of  least  resistance. 

Our  conclusion  would  be,  then,  that  in  the  case  of  a  given  irritation  in  a  sym- 
pathetic area,  as  in  cardiac  valvular  lesion,  the  sympathetic  reports  the  pain  to 


270  PRACTICAL   ANATOMY. 

the  cardiac  plexus  ;  this  plexus,  however,  transmits  the  impulse  to  the  nearest 
somatic  nerves,  which  greatly  intensify  the  pain,  and  refer  the  same,  peripher- 
ally, to  the  chest,  left  shoulder,  forearm,  and  fingers,  by  the  intercostals, 
descending  branches  of  the  cervical  plexus,  internal  cutaneous,  median,  ulnar, 
and  radial  nerves.  Thus,  a  pain  that  was  reported  as  simply  "aching,"  in  the 
locality  of  the  lesion,  under  poor  transmissional  conditions,  becomes,  under  the 
better  transmissional  conditions  of  somatic  nerves,  a  pain  dartijig,  stabbing,  and 
excruciating. 

Branches  of  the  Abdominal  Aorta  and  Sympathetic  Nerves. — I  now 
desire  you  to  dissect  the  branches  of  the  abdominal  aorta  with  special  reference 
to  the  sympathetic  nerves.  This  is  logical,  since  the  sympathetic  accompanies 
every  artery  to  its  visceral  end,  takes  the  very  name  of  the  artery,  and  regulates 
the  amount  of  blood  each  organ  shall  receive,  both  in  health  and  disease.  The 
sympathetic  reports  to  the  cortical  sensory  areas  in  the  cerebrum  sensations,  both 
of  pain  and  well-being,  through  the  vagus  and  all  the  spinal  nerves.  It  carries 
on  the  function  of  organs  during  suspension  of  volition. 

The  following  explanation  of  arrangement  will  give  you  a  clear  idea  of  the 
meaning  of  terms.  Before  you  proceed  further,  master  this  scheme  : 

i.  Every  artery  is  surrounded  by  a  plexus  of  small  nerves,  which  accompany 
the  artery  in  all  its  branches  to  the  organ  supplied  by  the  artery. 

Sensory  N.5*  < «« 


Moto 


6         Sensory  Branches  of  Anterior  Crural  * -^^ 

)  ^>x  Patella 

I     Motor  of  Anterior  Crural »»  >       ^^^^ 

Motor  t/ie  7?A  »» »  ,. 

X  face 


FIG.   187. — SHOWING  SCHEMATICALLY  A  MOTOR  REFLEX  CIRCUIT. 

2.  This  plexus,  which  always  takes  the  name  of  the  artery  it  accompanies, 
has  its  origin  in  a  ganglion  near  the  beginning  of  the  artery  on  the  aorta  ;  the 
plexus  also  takes  the  name  of  the  artery  which  its  branches  accompany. 

3.  The  ganglion — /.  e.,  all  the  ganglia  situated  at  the  beginning  of  all  the 
branches  of  the  abdominal  aorta — is  fed  by  nerves  from  the  solar  plexus. 

4.  The  solar  plexus  is  situated  in  front  of  the  beginning  of  the  abdominal 
aorta.      It  consists  of  two  large   semilunar  ganglia,  which   embrace    the    co-liac 
axis.     The   two  ganglia  are   connected  both  above  and  below  the  artery  which 
they  embrace.     The  plexus  is  formed  by  branches  from  the  vagus,  uniting  here 
with  the  sympathetic.     In  this  way,  then,  may  be  explained  the  manner  in  which 
the  vagus  reaches  all  the  abdominal  organs  with  motor  fibres. 

5.  The  solar  plexus,  then,  is  that  part  of  the  sympathetic  nerve  from  which 
all  the  abdominal  viscera  derive  their  nerve-supply.      It  is  situated  high,  but  is 
prolonged  downward  under  the  name  of  the  aortic  plexus.     From  this  the  gan- 
glia situated  at  the  beginning  of  the  branches  of  the  aorta  take  their  origin  ; 
these  ganglia  throw  off  plexuses  which  accompany  the  artery.     The  solar  plexus 
is  a  sort  of  clearing-house  for  the  abdominal  sympathetic  nerves. 

6.  From  above  down,  then,  the  succession  of  names  is  as  follows  :  (i)    '1  he 
solar   plexus,   formed  of  two    semilunar  ganglia;   (2)    the   dowmvard    prolong- 


ABDOMEN. 


271 


tion  of  the  solar  plexus,  called  aortic  plexus  ;  (3)  ganglia  situated  at  the  origin 
of  every  artery  from  the  aorta,  which  take  the  name  of  the  aorta  ;  (4)  branches 
or  plexuses  from  the  ganglia,  which  take  also  the  name  of  the  artery  and  accom- 
pany the  same  to  its  distribution. 

In  view  of  the  foregoing,  you  are  prepared  now  to  find,  locate,  explain,  and 
understand  : 

1.  Diaphragmatic  artery,  nerves,  plexus,  ganglion,  and  vein. 

2.  Splenic  artery,  nerves,  plexus,  ganglion,  and  vein. 

3.  Hepatic  artery,  nerves,  plexus,  ganglion,  and  vein. 

4.  Gastric  artery,  nerves,  plexus,  ganglion,  and  vein. 

5.  Suprarenal  artery,  nerves,  plexus,  ganglion,  and  vein. 

6.  Renal  artery,  nerves,  plexus,  ganglion,  and  vein. 

7.  Spermatic  artery,  nerves,  plexus,  ganglion,  and  vein. 

8.  Ovarian  artery,  nerves,  plexus,  ganglion,  and  vein. 

9.  Superior  mesenteric  artery,  nerves,  plexus,  ganglion,  and  vein. 
10.   Inferior  mesenteric  artery,  nerves,  plexus,  ganglion,  and  vein. 
Dissection  of  the  above  nerves  requires  care.     Work  in  the  direction  of  the 


Aorta 


SOLAR  PLEXUS,  THE  ABDOMINAL 
CLEARING-HOUSE  FOR  THE 
SYMPATHETIC  NERVE 


c  artery,  large 
SYMPATHETIC  NERVE,  CALLED  MESENTERIC 

A  MESENTERIC  GANGLION  ON  THE  AORTA 

FIG.  1 88.—  To  SHOW  RELATION  OF  ABDOMINAL  SYMPATHETIC  NERVES  TO  (i)  SOLAR  PLEXUS 

AND  (2\  TO  THE  GANGLION  AT  THE  R()OT  OF  THE  ARTERY. 


vessel,  with  forceps.  Consult  the  figures  heretofore  given  to  find  name  and 
location  of  vessels.  For  solar  and  aortic  plexuses  see  figure  186. 

Make  special  note  :  (i)  The  renal  veins  lie  in  front  of  their  arteries,  thereby 
forming  an  exception  to  the  rule  governing  the  relation  of  arteries  to  veins.  (2) 
The  left  spermatic  vein  opens  into  the  left  renal  vein,  and  this  latter  passes  in  front 
of  the  aorta.  (3)  The  right  spermatic  vein  opens  into  the  ascending  vena  cava  just 
below  the  renal.  (4)  The  ovarian  veins  follow  the  course  of  their  homologues. 
(5)  The  spermatic  arteries  arise  from  the  aorta  below  the  renals,  pass  in  front  of 
the  ureter  about  opposite  the  bifurcation  of  the  aorta.  The  ovarian  take  the 
same  course.  (6)  The  four  lumbar  arteries  are  analogous  to  the  intercostals. 
(7)  The  ureteric  arteries  accompany  the  ureters  ;  they  are  branches  of  the  common 
iliac  and  superior  vesicle.  (8)  The  arteries  to  the  vas  deferens,  to  the  urachus,  and  to 
the  ureter  are  branches  of  the  superior  vesicle.  (9)  The  sacra  media,  the  smallest. 

Essential  Points  on  the  Sympathetic. — You  have  traced  out  the  branches 
of  the  abdominal  aorta,  and  I  trust  you  now  understand  the  principle  under- 
lying the  distribution  of  visceral  nerve-branches,  from  one  abdominal  prevertebral 
plexus — the  solar  plexus.  We  shall  find  in  the  pelvis,  likewise,  organs  receiving 
arteries  ;  these  arteries  will  be  accompanied  by  sympathetic  nerves  ;  these  nerves 


272 


PRACTICAL  ANATOMY. 


GANGLION  DIAPHRA  GM.  I  IK  7  M/ 


SUPRARENAL 
CAPSULE 


ORE  A  T  8 PL  A  NCH- 

NIC  NER  VE 
RIGHT  SEMI  LU- 
NAR   GANGLION 


RENAL  GANGLION 

SMALL  SPLANCHNIC 
NERVE 

Renal  artery 


GANGLIA  TED  CORD 


RAMUS  COMMUNICANT 


Hepatic  artery 


BRANCH  TO  AORTIC 
PLEXUS 


LEFT  SEMI  LU- 
NAR  GANGLION 


(iHF.AT 

-V/r  NJ- 

SMA  LL  SI'LA  S<  'II- 


Superior  mesenteric 
artei-y 

RENAL  GANGLION 


Renal  artery 


SUPERIOR  MESENTERIC 
GANGLION 


BRANCH  TO  AORTIC 
PLEXUS 


GANGLIA  TED  CORD  OF 
SYMPA  THETIC 


Inferior  mesenteric  artery 


INFERIOR  .V/'N/'.v- 
TERIC  GANGLION 


Disc  between  last  lumbar 
and  first  sacral  vertebra 

('mil until  ilinc  rt  in 
Common  iliac  artei-y 


IMC.     I.S<J.  — I.CMIiAU      I'OKTHIN     01        I1IK     (  i  ANCI  I  \TKI  >     CORD,     WITH     Till.     Soi.AK      AM'    I  I V  l'(  )CAS  IK  U 

I'l.KXCSKS.       (I  It-Ill.',  i 


ABDOMEN.  273 

will  come  from  plexuses  on  the  artery  ;  these  plexuses  will  originate  in  ganglia 
near  the  origin  of  the  artery  ;  they  will  take  the  name  of  the  artery  and  trace 
their  own  origin  to  the  hypogastric  plexus.  We  shall  find,  in  the  thorax,  the 
heart  and  lung  concerned  in  the  circulation  of  the  blood  and  its  purification 
respectively.  These  organs  receive  their  nourishment  through  arteries,  and 
their  arteries  are  attended  by  nerves,  which  nerves  have  their  origin  in  plexuses  ; 
these  plexuses  spring  from  ganglia  near  the  origin  of  the  artery,  and  these 
ganglia  trace  their  own  origin  to  the  cardiac  plexus. 

There  is,  then,  one  great  sympathetic  depot  for  the  organs  in  the  thorax,  called 
cardiac  pie. rus  ;  one  in  the  abdomen,  called  solar  plexus  ;  one  in  the  pelvis,  called 
hypogastric  plexus.  This  arrangement  is  simply  to  make  possible  a  physiological 
division  of  labor.  Remember,  then  :  the  manner  of  distribution  of  sympathetic 
nerves  is  always  the  same  in  every  region  of  the  body  ;  branches,  plexuses,  and 
ganglia  take  the  name  of  the  artery  ;  there  are  three  large  plexuses — (i)  cardiac, 
(2)  solar,  (3)  hypogastric ;  there  are  as  many  small  plexuses  as  there  are 
arteries  to  supply  viscera — and  these  small  plexuses  all  draw  their  influence 
from  the  three  large  plexuses. 

In  view  of  what  we  have  found,  and  what  we  shall  find,  let  us  gain  a  general 
idea  of  the  sympathetic  system  in  the  following  questions  and  answers  : 

1.  Is  the  sympathetic  a  system,  separate  and  entire,   and  independent  of  the 
ccrebro-spinal  ? 

No  ;  sympathetic  nerves  are  only  nerves,  branches  of  the  spinals,  set  aside 
to  supply  organs. 

2.  Of  ivhat  docs  ttic  sympathetic  system  consist  f 

(i)  Of  gangliated  cord,  in  the  form  of  a  horse-collar,  communicating  on  the 
anterior  communicating  artery  above  and  on  the  coccyx  below  ;  (2)  of  spinal 
branches,  called  rami  communicantes — two  from  each  spinal  nerve  ;  (3)  of  three 
prevertebral  plexuses — cardiac,  solar,  and  hypogastric  ;  (4)  of  branches  of  distri- 
bution ;  (5)  of  plexuses  and  ganglia  that  take  the  name  of  the  arteries  on  which 
found. 

3 .  Can  iv e  see  the  nerves  and  ganglia  / 

Yes  ;  in  the  thorax  behind  the  pleura,  and  located  opposite  the  heads  of  the 
ribs,  you  can  seethe  ganglia  ;  you  can  also  find  the  two  communicating  branches 
from  the  spinal  nerves  ;  also  the  cord  extending  from  one  nerve  to  another. 

The  Hypogastric  Plexus. — In  the  lumbar  region  you  will  find  the  gangli- 
ated cord  on  the  front  of  the  bodies  of  the  vertebrae,  along  the  inner  margin  of 
the  psoas  magnus.  You  can  trace  branches  to  the  lumbar  nerves  behind  the 
psoas  magnus.  You  will  see  numerous  branches  from  the  lumbar  cords,  uniting 
with  branches  coming  down  from  above  to  form  the  hypogastric  plexus.  This 
is  between  the  common  iliac  arteries  and  passes  down  to  form  the  pelvic  plexus. 


THE  PELVIS. 


DISSECTION  OF  THE  PELVIS. 

Inspect  and  become  familiar  with  the  following  : 

1.  The  pelvic  contents  are  covered  by  peritoneum. 

2.  The  rectum  is  on  the  posterior  wall  of  the  pelvis. 

3.  The  bladder  is  on  the  anterior  wall  of  the  pelvis. 

4.  The  obturator  nerve  and  vessels  are  on  the  outer  wall. 

5 .  The  ureter  crosses  into  the  pelvis  and  can  be  seen. 

6.  The  uterus  and  adnexa  are  between  bladder  and  rectum. 

7.  The  broad  ligament  contains  the  uterine  adnexa. 

8.  The  recto-vesical  poucli  is  between  the  rectum  and  bladder. 

9.  The  peritoneum  does  not  cover  the  anterior  surface  of  bladder. 

10.  Retzius'  space  is  between  bladder  and  pubes. 

1 1.  The  recto-vaginal,  recto-uterine,  and  cul-de-sac  of  Douglas. 

12.  Douglas'  cid-de-sac  is  between  the  rectum  and  vagina  and  uterus. 

13.  Ilciun  and  great  ojnentum  gravitate  into  the  pelvis. 
Follow  this  order  in  your  dissection  : 

1 .  The  peritoneal   ligaments  of  the  bladder,   rectum,   and   uterus,  and  the 
sympathetic  nerves  from  the  pelvic  part  of  the  hypogastric  plexus  to  the  same 
viscera,  noticing  they  invariably  follow  the  arteries  to  the  organ,  and  take  the 
name  of  the  artery. 

2.  The  pelvic  fascia  and  its   subdivisions   and  modifications  incident  to  use, 
remembering,  as  you  must,  that  growth  is  the  correlative  of  function.      Notice, 
too,  that  pelvic  fascia  is  condensed  subperitoneal  connective  tissue.     The  upper 
or  uncondensed  portions  of  the  pelvic  fascia  contain  fat. 

3.  Study  the  relations  of  the   psoas  carefully ;  as  nearly  as  may  be,  follow 
the  steps  just  as  given  in  the  sequel,  for  this  is  the  order  in  which  you  will  meet 
all  these  various  structures  in  your  dissection. 

4.  The  lumbar  plexus  ;  its  location  in  the  substance  of  the  psoas  muscle  ;  its 
formation  by  the  four  upper  lumbar  nerves  and  a  communicating  branch  from 
the  twelfth  thoracic  ;   and  its  immense  distribution. 

.5.  The  internal  iliac  artery  and  all  its  branches,  where  the  same  escape  froi 
the  pelvis,  the  spinal  nerves  they  accompany,  and  the  source  of  the  sympathetic 
nerves  that  encircle  them  to  supply  the  viscera. 

6.  A  view  of  the  ischio-rectal  fossa  from  above,  by  cutting  the  origin  of  the 
levator  ani  muscle  at  the  white  line  and  looking  in   on  the  obturator  interims 
muscle  that  forms  its  outer  wall. 

7.  The  sacral  plexus,  its  location,  relations,  communications,  and  branches 
distribution,  and  where  these  large  branches  escape  from  the  pelvis. 

8.  In  addition  to  the  above,  make  dissection  and  study  of  the  iliacus  (origin 
of),  the  pyriformis,  the  levator  ani,  the  obturator  interims,  the  white  line  of  the 
pelvis,  and  the  delamination  in  the  obturator  fascia,  called  Alcock's  canal. 

In  order  to  estimate  the  peritoneal   ligaments   in  any  peritoneal    region,  asl 
yourself  how  many  viscera  of  considerable  size  grew  up  behind  this  membram 

274 


THE  PELVIS.  275 

and  pushed  the  same  before  themselves.  In  the  pelvis,  the  bladder,  rectum,  and 
uterus  grew  up  and  developed  behind  the  peritoneum  ;  hence,  not  only  are  these 
three  structures  behind  the  peritoneum,  but  all  their  adnexal  parts  as  well ;  they 
are  held  in  position  more  or  less  by  the  peritoneum,  and  those  processes  having 
one  end  on  the  organ  and  the  other  fixed  to  a  wall  are  called  the  peritoneal 
ligaments  of  these  organs.  Inflate  the  bladder,  and  see,  posteriorly,  two  folds 
extending  from  the  rectum  to  the  bladder  ;  also  a  fold  on  each  side  from  the  iliac 
fossa  to  the  side  of  the  bladder.  The  plica  urachi  is  the  superior  ligament  of  the 
bladder.  The  peritoneal  ligaments  of  the  bladder  are  tivo  posterior,  two  lateral^ 
and  one  superior. 

The  Rectum. — -The  rectum  begins  at  the  pelvic  brim,  opposite  the  left  sacro- 
iliac  synchondrosis.  You  will  ligate  and  cut  the  same  at  this  point,  leaving  the 
sigmoid  in  situ.  Notice  that  the  upper  part  of  the  rectum  has  a  fold  of  peri- 
toneum— the  meso-rectum.  The  next  stage  of  the  rectum  is  partially  covered 
by  peritoneum,  like  the  descending  colon.  The  lower  part  of  the  rectum,  one 
and  one-half  inches  in  length,  and  extending  from  the  tip  of  the  coccyx  to  the 
anus,  has  no  peritoneum,  as  you  will  see  on  the  cadaver.  Now  search  beside 
the  rectum  and  bladder  and  you  will  find  the  pelvic  plexus  of  sympathetic 
nerves,  which  supplies  all  the  viscera  in  the  pelvis.  Here,  as  elsewhere,  the 
nerves  accompany  the  arteries  to  the  parts  and  take  the  same  name. 

The  pelvic  fascia  is  the  lower  condensed  layer  of  the  subperitoneal  connec- 
tive tissue.  It  takes  the  following  different  names  :  iliac,  obturator,  recto-vesical,. 
pubo-prostatic,  anal,  white  line,  Alcock's  canal — according  to  its  location.  The 
white  line  you  will  see  extending  from  the  ischial  spine  to  the  pubic  bone,  one 
inch  below  the  subpubic  arch.  It  is  a  split  in  the  obturator  fascia,  from  which 
split  arises  the  levator  ani  muscle.  (Fig.  192.)  The  anal  fascia  covers  the  under 
surface  of  the  levator  ani  muscle.  The  recto-vesical  fascia  extends  across  the 
upper  surface  of  the  levator  ani  muscle,  investing  the  rectum  and  bladder.  It 
also  extends  from  the  pubes  to  the  neck  of  the  bladder  and  prostate,  under  the 
name  of  pubo-prostatic.  Demonstrate  all  these  on  the  cadaver. 

The  iliac  fascia  covers  the  iliacus  muscle,  passes  out  of  the  pelvis  behind 
the  femoral  vessels,  and  unites  with  the  transversalis  fascia  by  the  side  of  the 
femoral  vessels  to  form  the  femoral  sheath,  as  described  on  page  235. 

The  obturator  fascia  covers  the  obturator  internus  muscle  and  delaminates 
to  form  the  wJiite  line.  (Fig.  192.) 

Relations  of  the  Psoas  Magnus  Muscle. — (i)  Lying  on  the  muscle  you  see 
the  psoas  parvus  ;  (2)  to  the  outer  side,  see  the  iliacus  muscle  and  the  anterior 
crural  nerve  ;  (3)  to  the  inner  side,  skirting  the  pelvic  brim,  the  common  and  exter- 
nal iliac  arteries  are  seen  ;  (4)  to  the  inner  side,  and  one-half  of  an  inch  below  the 
pelvic  brim,  see  the  obturator  nerve  and  vessels  ;  (5)  emerging  from  the  front  sur- 
face of  the  middle  third  of  the  muscle,  see  the  external  cutaneous  nerve  ;  (6)  to 
the  inner  side,  between  the  muscle  and  the  common  iliac  artery,  see  the  genito- 
crural  nerve  ;  (7)  to  the  outer  side  of  the  muscle,  above,  see  the  last  thoracic,  the 
ilio-kv pogastric ,  and  the  ilio-fnguinal  nerves  ;  (8)  in  the  substance  of  the  muscle, 
this  having  been  detached  and  removed  piecemeal  with  the  forceps  from  within 
outward,  see  the  lumbar  plexus,  giving  off  the  following  branches. 

Branches  of  the  Lumbar  Plexus  (Fig.  190). — Dissection  : 

1.  I lio-Jiy pogastric,  to  the  skin  over  the  gluteus  maximus  and  over  the  hypo- 
gastrium  ;    lies    between  the  internal    oblique   and   transversalis  ;  communicates 
with  the  last  dorsal.     The    hypogastric  branch   pierces  the  aponeurosis   of  the 
external  oblique  muscle  one  inch  above  the   external  abdominal  ring,  and  is  dis- 
tributed to  the  skin  over  the  region  of  the  bladder. 

2.  Ilio-inguinal,  crosses  the  quadratus  and  iliac  muscles,  pierces  the  trans- 
versalis, lies  between  the  internal  oblique  and  transversalis,  supplies  the  internal 


276 


PRACTICAL  ANATOMY. 


oblique,  lies  in   front  ot   the  spermatic  cord  in  the  inguinal  canal,  escapes  by  the 
external  abdominal  ring,  and  supplies  the  scrotum  and  inner  side  of  the  thigh. 

3.  Gcnito-erural,  descends  on  the  front  surface   of  the  psoas  magnus,  divides 
into  a  genital  and  a  crural  branch  ;  the  genital  branch  enters  the  internal  abdom- 
inal ring,  lies  behind  the  spermatic  cord,  and  is  distributed  to  the  cremaster  mus- 
cle.     In    the  female   it  goes  with  the    round  ligament,  supplies  the   same    with 
motion,  and  is  lost  in  the  labia  majora. 

4.  The  crural  branch  of  this  nerve  descends  on  the  external  iliac  artery,  lies 
in  the  femoral  sheath,  and  is  distributed  to  the  skin  covering  the  insertion  of  the 
psoas — according  to  Hilton's  law. 


GANGLIATED  CORD  OF  SYMPATHETIC 
LAST  THORACIC  NERVE 


FIRST  LUMBAR 


ILIO- 

HYPOGASTRIC 
ILIO-INGUINAL 

SECOND 
LUMBAR 


FOURTH 

LUMBAR 

ILIO-INGUINAL 

EXTERNAL 

CUTANEOUS 

GENITO-CRURAL 
LUMBO-SACRAL 

CORD 

ANTERIOR  CRURAL 
OBTURATOR 

OBNTTAl.  BRANCH 
OF  OEXITO-CRURAL 

CRURAL  BRANCH  OP 
GEXITO-CRURAL 

ILIO-INGUINAL 


DISTRIBU- 
TION OF 
EXTERNAL 
CUTANEOUS 

CRURAL 
BRANCH 
OF  GENITO- 
CRURAL 


AORTIC  PLEAT* 

LAST  THORA  CIC  NER  VE 


ILIO-HYPO- 
QA8ZRIC 


INGUINAL 


THIRD 
LUMBAR 


GENITO- 
CRURAL 


EXTERN  A  L 
CUTANEOUS 

GENITAL 
BRANCH 
OF 

GENITO- 
CRURAL 

CRURAL 
HKA.\CH   OF 
(i KM  Til 
CRUMAL 

ourr- 

RATOl 


FIG.   190. — BRANCHES  OK  TIIK  I,t  MI.AR  AND  SACRAL  PLEXUS,  VIIAVKK  i  ROM  BEFORE, 
(After  Hirschfeld  and  Leveilte.J 


5.  External  cutaneous,  emerges  from  the  outer  side  ot    psoas,  crosses  iliacus 
under  the    iliac  fascia,  leaves  pelvis    under   crural  arch,  below  anterior  superior 
spine  of  ilium,  pierces  deep  fascia  of   thigh,  and  supplies  skin  over  outer  side  of 
thigh,  being  a  dismembered  branch  of  the  anterior  crural  nerve,  in  reality. 

6.  Obturator,  emerges  from  psoas  on  inner  side,  lies  on  outer  wall  of  pelvi 
leaves  pelvis  by  obturator  foramen,  divides  into  .anterior  and  posterior  divisions, 
separated  by  the  adductor  brevis  muscle  ;  the  anterior  division  communicates  with 
the    internal    cutaneous    and    long    saphcnous   nerves,   forming  the    subsartori 
plexus  for  the  supply  of  the  skin   over  the  insertion  of  the  adductors — llilto 


01 

,. 


THE   PELVIS. 


277 


laic.  It  then  supplies  the  gracilis,  adductor  longus,  adductor  brevis,  and  sar- 
torius.  The  posterior  division  supplies  the  hip,  knee,  obturator  externus,  and  ad- 
ductor magnus. 

7.  Accessory  obturator  often  absent ;  when  present  it  lies  to  the  inner  side  of 
the  psoas,  passes  under  outer  border  of  pectineus,  supplying  this  muscle  and  the 
hip-joint. 

Common  iliac  artery 
SYMPA  THE  TIC  NER  YE 

Middle  sacral  artery 
\ 


Common  iliac  vein 

URETER 

Internal  iliac  artery 

External  iliac  vein 
External  iliac  artery 

Posterior  branch  of  internal  iliac  dividing  into 
gluteal  <tn<l  ilitj-ltitnbar  arteries 

Lateral  sacral  arte 

SACRAL  PLEXUS 
OBTURA  TOR  NERVE 

Obturator  artery 
Obliterated  hypogastric 

Superior  vesical  artery 
Edge  of  levator  ani 

Pudic  artery 

BLADDER 

Middle  vesical  artery 

Deep  epigastric  artery 
Pubic  branch,  of  epi- 
gastric artery 
Common  femoral  artery 

Long  saphenotis  vein  — 
Pectineus  muscle 

Obturator  artery 

Adductor  magnus 

Internal  circumflex  artery 

Adductor  brevis 

OBTURATOR  NERVE  (ant.  branch) 

Profunda  artery 

Adductor  longus,  hooked  aside 

Superficial  femoral  artery  and  vein 


Gracilis  muscle 
Lower  part  of  sartorius 


Fsoas  muscle 
Ilio-lumbar  artery 

EXTERNAL  CUTA- 
NEOUS NERVE 

Iliacus  muscle 

,     GENITO-CRURAL 
44-     NER  VE 

ANTERIOR  CRU- 
RAL NERVE 


Deep  circumflex  iliac 

artery 
Superficial  circumflex 

iliac  artery 

—  ANTERIOR  CRL'RAL  ff. 
Gluteal  artery  and 

Tensor  taciae  femoris 

(hooked  aside) 
Gluteus  medius  and 

minimus 
Sartorius  muscle 
MIDDLE  CUTA- 
NEOUS NERVE 

NER  VE  TO  RECTUS 

NERVE  TO  VA STL'S 
ESTERXUS 

External  circumflex  ar, 

NERVE  TO  CRCREUS 
-J^a»«  Rectus,  hooked  aside 
T~V        Profunda  vein 

LONG  SA PHENOL'S 
NERVEAND 
NERVE  TO  VAS- 
TUS INTERNUS 


Vastus  internus 
muscle 


FIG.  191. — SIDE  VIEW  OF  PELVIS  AND  UPPER  THIRD  OF  THIGH,  WITH  THE  EXTERNAL  ILIAC, 

INTERNAL  ILIAC,  AND  FEMORAL  ARTERIES  AND  THEIR  BRANCHES. 

(From  a  dissection  by  W.  J.  Walsham  in  the  Museum  of  St.  Bartholomew's  Hospital.) 

The  bladder  is  hooked  over  to  expose  back  of  pelvis. 


8.  Anterior  cniral,  emerges  between    the   iliacus   and   psoas   muscles,  under 
crural  arch  or  Poupart's  ligament,  lies  in  a  groove  between  these  muscles  under 
the   iliac  fascia  ;  it  gives  off  the  internal   cutaneous,  middle  cutaneous,  and  long 
saphenous  branches.    Its  muscular  branches  are  to  the  sartorious,  rectus  femoris, 
vastus  internus,  vast  us  externus,  and  crureus.      The  branches   to   the   vasti   also 
send  filaments  to  the  knee-joint ;  the  branch  to  the  rectus  sends  a  filament  to  the 
hip-joint — Hilton's  law. 

9.  T/tc  lumbar  nerves  send  ranii  coinuiiinicantes  to  the  hypogastric  plexus. 


278 


PRACTICAL  ANATOMY. 


10.  The  dorsi-lumbar  cord  is  the  communication  of  the  first  lumbar  with  the 
last  thoracic  nerve ;  the  himbo-sacral  cord  is  the  communication  of  the  lumbar 
plexus  with  the  sacral  plexus.  Find  these  two  cords  on  the  cadaver. 

Dissection  of  the  Internal  Iliac  Artery  (Fig.  191). — The  common  iliac  artery 
divides  into  the  internal  and  external.  Use  only  the  forceps  when  you  develop 
branches  of  vessels.  Follow  the  direction  of  the  artery  and  its  branches  as  they 
are  given  off,  and  find  : 

1.  The  ureter,  crossing  into  the  pelvis  at  the  bifurcation  of  the  common  iliac 
artery,  and  its  small  ureteric  in  its  sheath. 

2.  The  bladder  being  inflated,  find  the  three  vesical  arteries — superior,  middle, 


Aperture  for 

superior  gluteal 
vessels  and  nerve 


Aperture  for 
sciatic  and  pudic 
vessels  and  nerve 


Coooygeal  fibres  of 
levator  ani 


Fibres  of  leva- 
tor  ani 


Sphincter  ani 
RECTUM 


•  White  line '  of 
obturator  fascia 


Pubic  attachment 
of  levator  ani 


Tendinous  centre 
of  periuitum 


FIG.  192. — MUSCI.KS  OF  'fiiK   FLOOR  OK  THK  PKLVIS. 
(A  portion  of  the  ischial  and  pubic  bones  sawn  away.) 


and  inferior.      In   connection   with  the  superior  vesieal,  find   the    obliterated  Jiyt 
gastric  artery. 

3.  Find  also  the  middle  luemorrlioidal,  to  the  rectum,  in  company  with  syt 
patlictie  nerves  from  the  pelvic  plexus. 

4.  Find  the  uterine  artery  (  Fig.  204)  passing  between  the  folds  of  the  brc 
ligament  of  the-  uterus. 

5.  Find  the  -vaginal  arteries,  three    or   four  in   number,  anastomosing   wit 
die  another  and  with  the  uterine. 

6.  Trace  the  ilio-lnmbar  between   the  psoas  magnus  and  vertebral   columi 
at  this  point  see  it  divide  into  an  iliac  and  a  lumbar  branch. 


THE   PELVIS.  279 

7.  Trace  out  the  lateral  sacrals  to  the  spine  and  front  of  the  sacrum. 

8.  Follow    the    superior  gluteal   out    of  the   pelvis  above   the  pyriformis, 
through  the  greater  sacro-sciatic  foramen,  with  a  nerve  of  the  same  name. 

9.  Follow   the   obturator  vessels    below   the   obturator   nerve   through   the 
obturator  foramen  to  the  adductor  muscles. 

10.  Observe  the  internal  pudic  leave  the  pelvis   by  the   greater  sacro-sciatic 
foramen  below  the  pyriformis,  cross  the  ischial  spine,  reenter  the  pelvis  by  the 
lesser   sacro-sciatic   foramen,  and   pass   through  Alcock's   canal  to   supply  the 
external   organs    of  generation   in  both   the   male  and   female.      This  artery  is 
attended  in  its  course  by  the  internal  pudic  nerve. 

1 1.  The  sciatic  artery  is  a  large  and  important  vessel.      It  crosses  the  pyri- 
formis  muscle   and   sacral   plexus  and   leaves  the  pelvis  by  the  greater  sacro- 
sciatic  foramen  below  the  pyriformis  muscle,  in  company  with  the  internal  pudic 
and  sciatic  nerves.      The  artery  lies  under  the  gluteus  maximus  muscle  and  on 
the  external  rotation  of  the  thigh.      It  gives  off  the  inferior  gluteal  artery,  which 
anastomoses  with  the  superior,  and  also  branches  to  the  pelvic  floor  and  pelvic 
viscera  ;  branches  to  the  rotator  muscles,  and  the  arteria  comes  nervi  ischiadici, 
a  branch  that    accompanies  the   great  sciatic  nerve.      This  artery  completes  the 
crucial   anastomosis,  an  important  collateral  circulation  about  the  hip-joint,  by 
inosculating   below  with  the   first  perforating  branch   of  the   profunda,  with  the 
internal  circumflex  internally,  and  with  the  external  circumflex  externally. 

The  sympathetic  distribution  in  this  region  will  correspond  to  the  visceral 
branches  given  off  from  the  internal  iliac  artery.  The  bladder  will  receive  its 
supply  by  the  vesicals  ;  the  uterus  by  the  uterine  ;  the  ovary  by  the  ovarian  ; 
the  rectum  by  the  hemorrhoidals — superior,  middle,  and  inferior  ;  the  urethra  and 
erectile  tissue  of  penis  and  clitoris  by  the  internal  pudic.  Remember  the  order : 
(i)  nerve;  (2)  plexus;  (3)  ganglion.  All  trace  their  sympathetic  influence  to 
that  part  of  the  sympathetic  located  in  the  pelvis,  by  the  side  of  the  bladder,  rec- 
tum, vagina,  and  uterus — the  pelvic  plexus. 

The  Obturator  Internus. — Cut  through  the  levator  ani  muscle  the  whole 
length  of  the  white  line,  from  spine  of  ischium  to  pubic  bone  ;  you  may  now  look 
down  into  the  ischio-rectal  fossa,  and  see  the  obturator  internus  muscle  covered 
by  the  obturator  fascia,  forming  the  outer  wall  of  this  fossa  ;  you  can  now  appre- 
ciate the  origin  of  the  levator  ani  from  the  white  line  and  the  cut  segment  of  the 
muscle,  and  study  both  the  inner  and  outer  walls  of  the  ischio-rectal  fossa.  (Fig. 
192.)  You  will  also  detach  the  pyriformis,  at  its  origin,  from  the  anterior  surface 
of  the  sacrum.  Observe  it  passing  through  the  greater  sacro-sciatic  foramen. 
You  will  also  see  the  coccygeus  muscle  extending  from  the  spine  of  the  ischium  to 
the  side  of  coccyx.  Now  find  on  the  outer  wall  of  the  ischio-rectal  fossa,  in 
Alcock's  canal,  the  internal  pudic  structures  ;  trace  the  same  forward  and  see  the 
relation  they  bear  to  the  tuber  ischii  and  the  triangular  ligament,  where  they 
perforate  the  posterior  layer  of  this  latter,  to  enter  the  deep  perineal  space. 

The  ischio-rectal  fossa  is  bounded  by  the  obturator  internus  muscle  exter- 
nally, by  the  levator  ani  internally  ;  its  apex  is  at  the  white  line  ;  it  extends  from 
the  pubic  bone  in  front  to  the  sacrum  behind  ;  the  base  is  formed  by  the  skin  and 
fasciae.  When  you  dissect  the  pelvic  outlet,  you  approach  this  fossa  from  the 
base.  In  the  present  dissection,  however,  you  approach  the  fossa  from  above. 
When  you  cut  through  the  white  line,  you  opened  into  the  fossa.  You  then 
pulled  the  levator  ani  muscle  to  the  mid-line  ;  this  levator  ani  muscle  with 
its  investing  anal  fasciae,  above  and  below,  is  the  inner  wall  of  the  fossa,  and 
you  are  thus  permitted  to  see  the  outer  wall  of  the  fossa — the  obturator  internus 
muscle — covered  by  the  obturator  fascia. 

Iliacus  Muscle.  —  Detach  this  muscle  from  its  extensive  origin  in  the  iliac 
fossa,  and  find  under  the  same  the  iliac  branches  of  the  ilio-lumbar  artery — a 


280 


PRACTICAL  ANATOMY. 


branch  of  the  internal  iliac  artery.      Find  the  groove   between    this  muscle   and 
the  psoas,  containing  the  anterior  crural  nerve. 

Dissection  of  Sacral  Plexus  (Figs.  193  and  194). — Cut  through  the  symphysis 
pubis  and  pull  outward  on  both  pubic  bones,  and  separate  the  ilium  from  the 
sacrum,  at  the  sacro-iliac  synchondrosis.  Then  study  the  following  points  : 

1.  The  plexus  is  located  on  the  posterior  pelvic  wall. 

2.  It  rests  on  the  pyriformis  muscle. 


FROM  LAST  THORACIC 


GENITO-CR  URA  L 

ILIO-HYPOGASTRIC 

ILIO-INGUINAL 


EXTERNAL 
CUTANEOUS 


OBTURATOR 


A CCESSOR  Y 
OBTURA TOR 


BRANCH  TO  ILIACUS 
ANTERIOR  CRURAL 


SUPERIOR  GLUTEAL 
INFERIOR  GLUTEAL 


GREAT  SCIATIC 

NERVE  TO 

qUADRATUS 

FEMORIS 


EXTERNAL 

POPLITEAL 

SECTION 

INTERNAL 
POPLITEAL 

SM'TION 


FIRST  L  I'M  HA  R 


SECOND  L  UMBA  R 


THIRD  LUMBAR 


FO  UR  TH  L  UMBA  R 


,—  FIFTH  LUMBAR 


FIRST  SACRAL 


SECOND  SACRAL 


THIRD  SACRAL 

VISCERAL 
Fornril  SACRAL 

PERFORA  77  v; 

i -i  y.i.\7:or.v 
PERIN.KAL 
FIFTH  SACRAL 

NEKVK   TO   I'OfCYHKl-f! 

NER  VE  TO  LEVA  TOR 
AN! 


FIRST  COCCYCI-AL 


VISCERAL 


TO  HAMSTRINGS 


SMA  LL  SCI  A  TIC       P  UDIC 


NERVE  TO  OBTURATOR  INTERN  US 

FIG.  193. — DIAGRAM  OF  THE  LUMBAR  AND  SACRAL  PLEXUSES.     Modified  from  Taterson. 


3.  It  is  covered  by  the  pelvic  fascia  and  peritoneum. 

4.  It  is  crossed  by  the  internal  iliac  vessels. 

5.  The  gluteal  and  sciatic  arteries  transfix  it. 

6.  It  receives  the  fifth  and  part  of  the  fourth  lumbar  nerves. 

7.  The  part  received  from  the  lumbar  is  called  the  lutnbo-sacmil  cord. 

8.  The  tacral  [>lc.\ v/.v  is  formed  by  the   union  of  the  lumbo-sacral   cord  and 
the  anterior  primary  divisions  of  the  first,  second,  third,  and  a  part  of   the  fourth 
sacral  nerves. 


THE   PELVIS. 


281 


9.  This  union  is  called  s"acral  plexus  to  the  lower  margin  of  the  greater  sacro- 
sciatic  foramen,  where  it  continues  its  course  under  the  name  of  great  sciatic  nerve.. 

10.  The  sacral  nerves  all  send  rami  communicantes  to  the  pelvic  sympathetic 
plexus,  which  you  have  already  found,  located  to  the  inner  side  of  the  anterior 
sacral  foramina,  by  the  side  of  the  rectum  and  bladder. 

Dissection  :  (i)  Trace  the  first,  second,  and  third  sacral  nerves  as  far  into  the 
sacral  foramina  as  possible.  Notice  !  This  must  be  done  with  a  blunt  forceps, 


Hit"    Dura  mater  of  . 


LAST  TIIORA  CIC  NER  VE 


ILIO- 
HYPOGASTRIC 


77,70- 
INGU1NAL 


ILIAC  BRANCH 

OF  1LIO- 
HYl'OGASTRIC 


Gluteus  medius 

Gluteal  artery 
SUPERIOR 
GLUTEAL  NERVE 


ORE  A  T  SCIA  TIC  NER  VE 

INFERIOR  GLUTEAL 
NER  VE 

SMALL  SCIA  TIC  NER  VE 


POSTERIOR  PHI1UAHF 
DIVISION 


GENITO-CRURAL 


GAUD  A  EQUINA 


—  Pilum  terminate 


EXTERNAL 
\\         CUTANEOUS 


OBTURATOR 
Lr.MIto- SACRAL  CORD 


-, —  FIRST  8 A  CRA  L 
NER  VE 


FIFTH  SACRAL 
NER  VE 


VISCERAL  BRANCHES 
Si'inlii-  itrlery 

Small  sacro-sciatic 

ligament 
PUDIC  NER  VE 

NERVE  TO 
OBTURA  TOR 
INTERNUS 

PER  FORA  TING 
CUTANEOUS  OF 
SECOND      A  ND 
THIRD  SACRAL 
NERVES 


FIG.  194.  —  A  DISSECTION  OF  THE  LUMBAR  AND  SACRAL  PLEXUSES,  FROM  BEHIND. 
(The  anterior  crural  nerve  is  placed  between  the  external  cutaneous  and  obturator  nerves.) 

and  with  a  very  delicate  touch,  to  avoid  injuring  the  small  branches  given  off  to 
the  sympathetic  —  pelvic  part  of  the  gangliated  cord.  After  this  is  done,  all  the 
fat  must  be  dissolved  by  ether,  benzene,  or  gasoline.  (2)  Now  dissect  in  the 
direction  of  the  branches  given  off,  and  find  the  following  : 


BRANCHES  OF  THE  SACRAL  PLEXUS. 
i.    Tlic  lumbo-sacral  cord  is  the  communication  between  the  sacral  and  lum- 


bar plexuses. 
19 


It  is  formed  by  the  fifth  lumbar  and  part  of  the  fourth  lumbar — 


282  PRACTICAL   ANATOMY. 

anterior  primary  divisions.  This  must  now  be  located  on  the  ala  of  the  sacrum 
as  it  passes  down  into  the  pelvis,  and  its  union  with  the  first,  second,  and  third 
sacral  nerves  carefully  shown. 

2.  Muscular  brandies  to  the  pyriformis,  the  quadratus  femoris,  the  gemellus 
superior,    the  gemellus  inferior,  and  the  obturator  interims  muscles.      Notice  ! 
You    will  find  the  branch   to   the    obturator  internus,  leaving  the  pelvis  by  the 
greater  and   reentering  by  the  lesser  sacro-sciatic  foramen.      When  you  dissect 
the  structures  in  the  lesser  sacro-sciatic  foramen,  you  will  find  this  nerve  with  the 
internal  pudic  structures.     The  nerve  to  the  quadratus  femoris  and  gemellus 
inferior  leaves  the    pelvis  by  the  greater  sacro-sciatic  foramen,  and   supplies  a 
branch  to  the  hip-joint  as  well. 

.  You  will  trace  the  superior  gluteai  nerve  through  the  greater  sacro-sciatic 
foramen,  above  the  pyriformis  muscle,  to  the  gluteus  medius,  gluteus  minimus, 
and  tensor  vaginae  femoris.  The  skin  covering  these  muscles  is  not  sup- 
plied by  this  nerve -trunk  apparently,  but  by  the  ilio-hypogastric  and  lumbar 
cutaneous  branches  from  posterior  primary  divisions.  Now,  let  me  impress 
on  the  student  this  fact :  A  nerve-trunk  supplying  a  muscle  must  supply  the 
skin  covering  the  muscle,  or  the  serous  membrane  under  the  muscle, — it 
any  serous  membrane  be  present, — and  the  joint  moved  by  the  muscle.  The 
skin  branches,  in  the  majority  of  cases,  are  given  off  directly  from  the  nerve- 
trunk,  and  are  easily  found.  In  a  minority  of  cases,  however,  the  skin  branch  is 
not  given  off  directly,  but  comes  from  apparently  another  source  ;  to  such  cases  as 
these  I  see  no  impropriety  in  applying  the  terms  divorced,  dismembered,  or  erratic. 
Confirmatory  instances  of  divorced  skin  branches  are  to  be  found  in  the  small 
sciatic,  the  dismembered  cutaneous  branch  of  the  great  sciatic,  supplying  the 
skin  covering  the  muscles  supplied  with  motion  by  the  great  sciatic  nerve  ;  in  the 
external  cutaneous  nerve,  on  the  outer  part  of  the  thigh,  this  nerve  being  divorced 
from  its  parent  stem,  the  anterior  crural ;  in  the  long  pudendal  nerve,  or  nerve  of 
Soemmering,  the  dismembered  branch  of  the  internal  pudic  nerve,  following,  in- 
deed, a  most  erratic  course,  ensconced  in  the  sheath  of  the  small  sciatic  nerve  ; 
in  the  descendens  hypoglossi,  a  divorced  branch  of  the  cervical  plexus.  In  view 
of  the  occurrence  of  anomalies,  then,  you  are  to  ask  yourselves,  when  dissecting 
mixed  nerves  :  Have  I  found  (i)  muscular  branches,  (2)  cutaneous  branches,  (3) 
articular  branches  ?  and  (4)  are  the  cutaneous  branches  direct  descendants  of  tin 
nerve -trunk,  or  are  they  divorced  therefrom  ? 

3.  The  inferior  gluten!  nerve  leaves  the  pelvis    by  the  greater   sacro-sciati( 
foramen  below  the  pyriformis  muscle  and  supplies  the  gluteus  maximus. 

4.  The  perforating  cutaneous  nerve  will  be  found  when  you  dissect  the 
region,  coming  through  the  greater  sacro-sciatic  ligament  to  supply  the  skin  ii 
this  region. 

5.  The  internal  pudic  nerve  is  remarkable  for  the  great  number  of  important 
areas  in  which  it  and  its  branches  are  found.      It  leaves  the  pelvis  by  the  greater 
sacro-sciatic  foramen  below  the  pyriformis  muscle,  crosses  the  ischial  spine,  reen- 
ters    the  pelvis  by  the  lesser  sacro-sciatic  foramen,  here  enters  Alcock's   canal, 
in  the  outer  \vall   of  the  ischio-rectal  fossa,  then  pierces  the  triangular   ligament, 
passes  through  the  deep  perineal  space,  again    pierces  the  triangular  ligament, 
passes  through  the  suspensory  ligament  of  the  penis  to  gain  the  dorsum  of  this 
organ.      In    its    course  'it  throws  off  the  following  branches  :     As  the  nerve  is 
entering  the  canal — Alcock's — it  gives   off  the    inferior    lieinorrlioulal    and    tin 
prrincal  branches.      These  pass  through  the  fat-bearing  ischio-rectal  fossa.      Th< 
inferior  hemorrhoidal  nerve  is   distributed  to  the  external   sphincter  ani    mnsclt 
and  the  skin  covering  the  same.     The  perineal  branch  is  distributed  to  the  accele- 
rator tirin;e,  transvcrsus    perin.ei.  erector   penis,   levator  ani,  compressor  urethra, 
and   to   the   skin   covering  the  scrotum  and  petineum.      The  internal  pudic  nerve 


THE  PELVIS.  283 

now  continues  its  course  in  Alcock's  canal,  and  through  the  deep  triangular  peri- 
neal  space,  under  the  name  of  dorsal  nerve  of  the  penis,  to  which,  with  the  sym- 
pathetic from  the  pelvic  plexus,  it  is  distributed. 

6.  The  small  sciatic  leaves  the  pelvis    by  the   greater   sacro-sciatic  foramen 
below  the  pyriformis,  and  breaks  up  into  four  principal   cutaneous   branches — 
ascending,  descending,  external,  and  internal.    The  largest  of  the  internal  branches 
crosses  the  tuberosity  of  the  ischium,  and  is  distributed  to  the  labia  majora  under 
the  name  of  inferior  pudendal,  or  nerve  of  Soemmering. 

7.  The  great  sciatic  nerve  takes  its  name  at  the  lower  border  of  the  greater 
sacro-sciatic  foramen,  through  which  you  see  it  leaving  the  pelvis  below  the  pyri- 
formis  muscle.      Examine   closely  and  you   can   see  some  very  small  branches. 
These  are  articular  to  the  hip-joint.     Lower  down  are  given  off  muscular  branches 
to  the  biceps  semitendinosus,  semimembranosus,  and  adductor  magnus  muscles. 
As  a   rule,  the   nerve   divides  six  inches  above  the  knee  into  the  internal  and 
external  popliteal  nerves. 

Branches  of  the  Internal  Popliteal  Nerve  of  Great  Sciatic  : 

1.  The  communicans  tibialis  to   the  communicans  fibularis,  a  branch   of  the 
external  popliteal  to  form  by  this  union  the  short  saphenous  nerve.     This  nerve 
supplies  the  skin  over  the  superficial  group  of  muscles  of  the  leg. 

2.  Articular-  branches  to  the  knee,  with  the  articular   arteries,  superior   and 
inferior  internal,  and  the  azygos. 

3.  Muscular  branches  to  the  gastrocnemius,  soleus,  plantaris,  and  popliteus. 

4.  Posterior  tibial,  which  gives  off  an  articular  branch  to  the  ankle  ;  a  plantar 
cutaneous   branch   to  the   heel   and  sole  of  foot   on   the  inner  side  ;    muscular 
branches  to  the  flexor  longus  digitorum,  tibialis  posticus,  flexor  longus  hallucis  ; 
a  communicating  branch  to  the  soleus  muscle. 

5.  The  internal  plantar,  which  gives  off  articular  branches  to  the  tarsus  and 
metatarsus,  digital  cutaneous  branches  to  the  four  lesser  toes,  muscular  branches 
to  the  abductor  hallucis,  flexor  brevis  digitorum,  flexor  brevis  hallucis,  and  the 
two  tibial  lumbricales. 

6.  Extei'nal  plantar,  that  supplies  one  and  one-half  toes  cutaneously  ;  mus- 
cular branches  to  flexor  accessorius,  abductor  minimi  digiti,  the  two  outer  lumbri- 
cales, the    adductor   hallucis    obliquus,   the    adductor  hallucis  transversus,   the 
flexor  brevis  minimi  digiti,  and  all  the  interossei  muscles. 

Branches  of  the  External  Popliteal  of  Great  Sciatic : 

1.  The  communicans  fibularis  to  the  communicans  tibialis  to  form  the  short 
saphenous  nerve. 

2.  Three  articular  branches  to   the   knee,  proceeding  with  the   superior  and 
inferior  external  articular  arteries  and  the  azygos. 

3.  Cutaneous  brandies  to  the  skin  covering  the  peronei  muscles,  being  given 
off  with  the  communicans  fibularis. 

4.  The  anterior  tibial  nerve,  which  gives  off  an  articular  branch  to  the  ankle, 
to   the   metatarso-phalangeal  joints   of  all   the   toes.     Muscular  brandies  to  the 
tibialis    anticus,  extensor  proprius  hallucis,  extensor  longus  digitorum,  extensor 
brevis  digitorum,  and  a  muscular  branch  to  the  first  interosseous  muscle. 

5.  The    musculo-cutancoiis,   which    gives   off   its   muscular    branches    to   the 
peroneus  longus   and   peroneus   brevis   muscles.     Cutaneous  branches,  internal 
and  external,  to   the  dorsum  of  the  foot,  communicating  with  the  internal   and 
external  saphenous  nerves. 

1 .  Where  is  the  lumbar  plexus  located  f 

It  is  behind  the  peritoneum  in  the  deep  substance  of  the  psoas  magnus  muscle. 

2.  How  is  tlie  lumbar  plexus  formed / 

By  the  union  of  the  anterior  primary  divisions  of  the  first,  second,  third,  and 
a  part  of  the  fourth  lumbar  nerves,  and  the  dorsi-lumbar  cord. 


284  PRACTICAL  ANATOMY. 

3.  \Vitli  what  docs  tlic  lumbar  plexus  communicate .' 

(l)  With  the  twelftli  thoracic  nerve,  by  a  branch  named  the  dor.si  lumbar  ;  (2) 
with  the  sacral  plexus,  by  a  branch  called  the  lumbo-sacral  cord  ;  (3)  with  the 
lumbar  part  of  the  gangliated  cord,  by  branches  called  rami  communicantes. 

4.  Describe  the  sympathetic  connection,  and  tell  Juw  to  conduct  a  dissection  of  the 
same  in  tins  region. 

The  lumbar  part  of  the  gangliated  cord  is  quite  easily  found  ;  the  communi- 
cations with  the  anterior  primary  divisions  of  the  lumbar  nerves  are  not  difficult 
to  trace  out.  The  double  chain  of  the  sympathetic  cord  consists  of  four  ganglia 
on  each  side  ;  these  ganglia  are  :  (l)  Right,  which  lie  behind  the  ascending  vena 
cava  ;  (2)  left,  which  lie  behind  and  slightly  external  to  the  aorta.  Find  the  cord 
communicating  above  with  the  thoracic,  and  below  with  the  pelvic  portion,  by 
continuity.  The  rami  communicantes  are  quite  long  in  this  region  ;  as  a  rule, 
they  are  two  in  number,  and  they  accompany  the  lumbar  arteries.  The  lumbar 
arteries,  then,  are  your  guide  in  tracing  the  relation  between  the  lumbar  plexus  of 
somatic  nerves,  and  the  lumbar  part  of  the  sympathetic  gangliated  cord. 

5.  Name  the  branches  of  the  lumbar  plexus. 

The  ilio-hypogastric,  ilio-inguinal,  genito-crural,  external  cutaneous,  anterior 
crural,  obturator,  accessory  obturator,  muscular  branches  to  the  psoas  magnus 
and  quadratus  lumborum,  and  the  lumbar  element  of  the  lumbo-sacral  cord. 

6.  Give  formation  and  location  of  the  lumbo-sacral  cord. 

It  is  formed  by  the  union  of  the  fifth  lumbar  nerve  and  a  part  of  the  fourth. 
In  practical  anatomy  you  find  it  buried,  in  a  considerable  quantity  of  fatty  con- 
nective tissue  behind  the  peritoneum,  on  the  ala  of  the  sacrum.  This  cord  gives 
origin  to  the  superior  gluteal  nerve,  described  previously. 

7.  Describe    the  genito-cniral   nerve,    and  give    its  practical   importance    in 
diagnosis. 

The  nerve  arises  from  the  first  and  second  lumbar  nerves.  It  lies  on  the  psoas 
magnus  muscle  in  the  lower  part  of  its  course.  It  divides  into:  (i)  A  genital 
branch,  which  follows  the  spermatic  vessels  and  supplies  the  cremaster  muscle 
with  motion.  In  practical  anatomy  you  find  this  branch  behind  the  spermatic  cord. 
(2)  A  cutaneous  branch,  the  crural,  which  is  distributed  to  the  skin  of  the  upper 
inner  part  of  the  thigh.  The  cremasteric  reflex  depends  on  this  nerve.  Irritate 
the  skin  of  the  thigh  corresponding  to  the  sensory  distribution  of  this,  the  genito- 
crural  nerve,  and  the  testicle  of  the  corresponding  side  will  be  elevated  by  the 
contraction  of  the  cremaster  muscle.  In  diagnosis,  the  movement  of  the  testicle 
thus  produced  argues  in  favor  of  the  integrity  of  the  spinal  cord  between  the  first 
and  second  lumbar  nerves.  In  the  female  this  nerve  is  rudimentary,  and,  there 
being  no  cremaster  in  this  sex,  the  genital  branch  of  the  nerve  is  distributed  tc 
the  round  ligament  of  the  uterus  ;  the  crural  branch  is  distributed  as  in  the  male. 
The  reflex  phenomena  in  the  female  are  recorded  as  a  twitching  of  the  external 
oblique  ;  still,  I  think  careful  observation  would  prove  such  record  erroneous.  Th< 
twitching  must  be  in  the  round  ligament  of  the  uterus,  since  this  is  the  homo- 
logue  of  the  spermatic  cord. 

8.  Describe  a  patellar  reflex  circuit  and  give  its  importance  in  diagnosis. 

The  anterior  crural  nerve  is  concerned  in  this  reflex.  Sensory  branches  from 
this  nerve,  distributed  over  the  insertion  of  the  quadriceps,  forming  the  plexus 
patella-,  convey  sensation  to  a  transfer  centre  ;  and  motor  branches  from  the 
anterior  crural  induce  contraction  of  the  extensor  group  of  muscles  on  the  fronl 
of  the  thigh.  flu's  reflex  movement  is  normal  in  health.  It  is  absent  in  loco- 
motor  ataxia  and  in  the  case  of  lesions  and  diseases  affecting  the  anterior  gray 
cornua  of  the  spinal  cord.  It  is  increased  after  epileptic  sei/ures,  in  spinal  irrit- 
ability, tumors  of  the  brain  and  disease-^  <>f  the  lateral  tracts  of  the  cord,  and  in 
lateral  and  c vivbro-spinal  sclerosis. 


THJ'.    PELVIS.  285 

9.   Explain  tJic  tecJinicjue  of  obtaining  knee-jerk,  or  patcllar  reflex  movement. 

(i)  Place  the  patient  in  the  sitting  posture  on  the  table,  with  his  legs  hanging 
at  right  angles  to  the  thighs  ;  (2)  blindfold  the  patient,  and  do  not  acquaint  him 
with  the  procedure  ;  otherwise,  through  nerve-influence  from  the  obturator  to  the 
sartorious  muscle,  phenomena  of  a  voluntary  nature  on  the  part  of  the  patient 
might  be  observed  which  would  cloud  your  diagnosis  ;  (3)  tap  the  ligamentum 
patellae  with  a  ferrule,  or,  better  still,  gently  prick  the  skin  over  the  same  with  a 
sharp  instrument.  Students  should  be  encouraged  to  practice  obtaining  these 
reflexes  on  one  another. 


DIAPHRAGM.     (Fie.  195.) 

Function. — Partition  between  thorax  and  abdomen. 
Superior  Serous  Relations. — Pericardium  and  pleurae. 
Inferior  Serous  Relations. — The  diaphragmatic  peritoneum. 
Structure. — A  musculo-membranous  sheet. 
Apertures. — CEsophageal,  aortic,  and  caval. 
Ligamentum  arcuatum  inter tiiun,  part  of  iliac  fascia. 
Ligamentum  arcuatum  cxternum,  part  of  lumbar  fascia. 
Central  tendon  forms  the  summit  of  the  dome. 
CEsophageal  opening  transmits  oesophagus  and  vagus  nerves. 
Aortic  opening  transmits  aorta  and  thoracic  duct. 
Caval  opening  transmits  the  ascending  vena  cava. 
Physiological  Action. — Deepens  the  chest. 
Nerve-supply. — The  two  phrenics  and  the  sympathetic. 
Source  of  Sympathetic  Nerve-supply. — Solar  plexus. 
Blood-supply. — The  phrenic  arteries. 

Source  of  Plirenic  Arteries. — Aorta,  renals,  and  intercostals. 
Hoiv  many  origins  lias  the  diaphragm  ? 

1.  Anterior  or  Sternal  Portion. — The  lower  border  and  back  of  the  ensiform 
cartilage   and  the  adjacent  part  of  the  back  of  the  anterior  aponeurosis  of  the 
transversalis  abdominis. 

2.  Lateral  or   Costal  Portion. — The   lower   border  and   inner  surface  of  the 
cartilages  of  the   six   lower   ribs,  and   sometimes   also   from  the  adjacent  part  ot 
the  ribs. 

3.  Posterior  or  Vertebral  Portion. — (i)  The  ligamentum  arcuatum  externum,  a 
fibrous  thickening  of  the   anterior   layer  of  the    lumbar   fascia,  which  stretches 
from  the  tip  of  the  transverse  process  of  the   second  lumbar  vertebra  to  the  tip 
of  the  last  rib  ;  (2)  the  ligamentum  arcuatum  internum — a  fibrous  thickening  of 
the  iliac  fascia,  which  arches  over  the   upper  part  of  the  psoas  from  the  sick-  of 
the  body  of  the  second  lumbar  vertebra  to  the  tip  of  its  transverse   process  ;  (3) 
the  cms  of  the  diaphragm — a  strong  vertical  band,  fleshy  externally,  tendinous 
internally,  arising   on   the  right  side  from  the  front  of  the  bodies  of  the  first  to 
the  third   or  fourth   lumbar  vertebra;:,  from  the   intervening  vertebral  discs,  and 
the  anterior  common   ligament ;   on  the  left  side,  from   the  bodies  of  the  first  to 
the   second   or   third  vertebrae    only,  as  well   as   the  discs  and  anterior  common 
ligament. 

Insertion. — The  front,  sides,  and  back  of  the  central  tendon. 

The  crura  are  perforated,  and  transmit  structures  as  follows  :  The  right,  the 
sympathetic  and  the  splanchnics  of  the  right  side;  the  left,  the  splanchnics  of 
the  left  side  and  the  vena  azygos  minor. 


286 


PRACTICAL  ANATOMY. 


Visceral  Relations. — On  careful  dissection  you  will  see  the  diaphragm  bears 
very  important  relations  to  the  following  structures  :  (i)  As  previously  indicated, 
the  superior  surface  of  the  diaphragm  is  occupied  by  the  three  serous  membranes. 
The  pulmonary  surface  of  the  diaphragm  corresponds  to  the  base  of  the  lung. 
The  cardiac  surface  corresponds  to  the  base  of  the  pericardium.  (2)  The  liver, 
stomach,  spleen,  kidneys,  and  suprarenal  capsules  are  in  relation  with  its  under 
surface.  (3)  The  aorta,  oesophagus,  ascending  vena  cava,  the  vena  azvgos  minor, 
the  pucumogastric  nerves,  the  splancJmics,  the  sympathetic — all  pass  through  the 
diaphragm.  (4)  Posteriorly,  the  diaphragm  arches  over  the  psoas  magnus  and 
the  quadratus  lumborum.  A  fibrous  arch,  formed  by  the  iliac  fascia,  arches  over 
the  psoas  ;  one  formed  by  the  anterior  layer  of  the  lumbar  fascia  arches  over  the 
quadratus  lumborum  muscle.  Consult  carefully  figure  195.  Lastly,  remove 
the  peritoneal  covering  of  the  diaphragm,  and  see  the  beautiful  manner  in  which 
the  fibers  from  the  three  different  sources  of  origin  approach  for  insertion  the 


Sternal  origin 


Opening  for  vena 
cava  inferior 


Right  division  of 
tendon 


Aorta  -  -i 


Bight  crus 
Psoas  parvus 


Psoas 

Transversalis 
abdominia 


Middle  division 
of  tendon 


(Esophagus 


Left  division  of 
tendon 


'.-  Costal  origin 


Ligamentum 

arouatum 

internum 
Left  crus 
Ligamentum 

arcuatum 

externum 
Transverse 

process  of 

second  lumbar 

vertebra 
Fourth  lumbar 
vertebra 


FIG.  195. — DIAPHRAGM. 

central  tendon.     The  central  tendon  corresponds  to  the  base  of  the  pericardium  ; 
the  fibrous  part  of  the  pericardium  is  the  downward  prolongation  and  expansioi 
of  the   third  layer  of  the  deep  cervical  fascia,  having  firm  bony  attachments  to 
the  base  of  the  skull  ;  hence,  in  deep  inspiration  it  is  not  the  central  tendon  that 
becomes  depressed,  but  the  muscular  part  of  tlie  diapliragm. 


I  Dissection  of  Av/>  Muscles  and  otlicr  Structures  of  tlic  Pelvis. — (i)   The  quad- 
ratus lumborum  ;  (2)  psoas  parvus  ;  (3)  psoas  magnus  ;  (4)  iliacus  ;  (5)  crura  o 
diaphragm  ;   (6)  anterior  common   ligament  of  vertebral   column  ;  (7)  obturator 
interims  ;    (8)  obturator  extern  us  ;    (9)  obturator   membrane;    (10)  pyriformis 
(i  i)  coccygeus  ;  (12)  levator  ani ;   (13)  white  line  of  the  obturator  fascia. 


THE   PELVIS. 


287 


Locate  on  your  cadaver:  (i)  The  iliac  fossa;  (2)  the  auricular  surface  of 
the  ilium  ;  (3)  the  tuberosity  of  the  ilium  ;  (4)  the  tuberosity  of  the  ischium  ;  (5) 
the  spine  of  the  ischium  ;  (6)  the  spine  of  the  pubes  ;  (7)  the  ilio-pubal  ridge  ; 
(8)  the  ilio-pectineal  line  ;  (9)  the  anterior  and  posterior  surfaces  of  the  pubes  ; 
(10)  the  ischio-pubic  ramus  ;  (11)  the  thyroid  or  obturator  foramen;  (12)  the 
symphysis  pubis  ;  (13)  the  anterior  superior  and  anterior  inferior  iliac  spines; 

Quadratus  lumborum 
I 


Erector  spinse 


TUBEROSITY 


AURICULAR  SURFACE 


POST.  INF.  SPINE  OF 
ILIUM 


Transversalis  and  the  iliac 
fascia 


GROOVE  FOR  PUDIC 

VESSELS  AND 

NERVE 

Qt.  sacro-sciatic 
ligament 


x^ 

JUNCTION  OF  PUBES       Crus  penis  and       Compressor  Subpubie 

AND  ISCHIUM  Erector  penis  urethras  ligament 

FIG.   196. — THE  LEFT  HIP-BONE.  (Internal  surface.) 


ANT.  SUP.  SPINE  OF 
ILIUM 


ANT.  INF.  SPINE  OF  ILIUM 


Fsoas  minor 


ILIO-PUBAL  RIDGE 


GROOVE  FOR  OBTURATOR 
NERVE  AND  VESSELS 


.SYMPHYSIAL  SURFACE 
Levator  ani 


(14)  the  posterior  superior  and  posterior  inferior  iliac  spines  ;  (15)  the  greater 
and  lesser  sacro-sciatic  foramina;  (16)  the  greater  and  lesser  sacro-sciatic  liga- 
ments ;  (17)  the  obturator  groove.  Locate  the  above  points  on  the  cadaver, 
and  in  the  progress  of  your  dissection  find  and  dissect  the  soft  structures 
attached  to  them  or  in  any  way  bearing  important  relations  thereto.  Study 
thoroughly  the  os  innominatum. 

Dissection. — Quadratus   Lumborum. — Find    the   origin    on   the    ilio-lumbar 


288 


PRACTICAL  ANATOMY. 


ligament  and  the  iliac  crest  for  two  inches.  Trace  the  muscle  to  its  insertion 
into  the  lower  border  of  the  twelfth  rib  and  into  the  transverse  processes  of  the 
four  upper  lumbar  vertebrae.  Now  place  the  kidney  in  its  original  position  on 
this  muscle.  This  muscle  lies  in  front  of  the  erector  spinse  muscle.  In  fact, 
these  two  muscles  form  a  guide  to  operations  on  the  kidney.  See  whether  you 
can  demonstrate  on  your  work  these  structures,  in  the  following  relation  from 
behind  forward  :  (i)  The  quadratns  linnbontin ;  (2)  the  lumbar  fascia;  (3)  the 
last  thoracic  nerve,  the  ilio-liypogastric  and  ilio-ingnhial  nerves  ;  (4)  the  fatty 
capsule  of  the  kidney  ;  (5)  the  kidney.  In  operations  on  the  kidney  from  behind, 


Quadratus  lumborum 


Faoaa  parvus 


Fsoaa  magnus 


Iliac  us 


Intertransversalis 
anterior 


Quadratus  lumborum 


IK;.  197. — PSOAS,  II.IACUS,  AND  QUADRATUS  LI;.MI;<>KI  M. 


you  would  find  the  above  relations.       Study  the  above  relations  until  you  ha> 
perfect  picture  of  all  these  Structures  ill  your  mind.     The  lower  end  of  the  kidney 
is  about  one  and  one-half  inches  above  the  iliac  crest. 

The  psoas  magnus  muscle  in  its  relation  to  vessels  and  nerves  has  been 
previously  described.  The  muse -le  has  a  strong  synergist  in  the  iliacus.  The-e 
two  are  sometimes  spoken  of  as  one  muscle,  with  two  heads  or  parts — the  i/io- 
/>so<ts.  The  two  muscles  are  inserted  into  the  lesser  trochanter  of  the  femur. 
My  this  action,  when  the  thigh  is  the  fixed  point,  they  draw  the  pelvis  forward, 
rotating  the  same  on  the  heads  of  the  femur.  They  thus  antagoni/c  the  glutcus 
•  maximus.  The  psoas  magnus  <7/-/.sv.v  from  the  sides  of  the  bodies  of  tin-  last  thor- 


THE   PELVIS. 


289 


acic  and  all  the  lumbar  vertebrae,  and  from  their  intercentral  cartilages  ;  from 
the  lower  border  of  the  transverse  processes  of  the  lumbar  vertebras.  The 
nerve-supply  is  from  the  lumbar  plexus.  The  nerve-supply  of  the  iliacus  is  from 
the  anterior  crural  part  of  the  lumbar  plexus. 

The  Iliacus. — Detach  from  its  origin  and  turn  it  down  to  its  insertion  into 
the  lesser  trochanter  of  the  femur  with  the  psoas  magnus.  This  is  a  flexor  of 
the  thigh  on  the  abdomen.  Its  synergist  is  the  psoas.  It  also  pulls  the  body 
forward,  when  the  thigh  is  made  the  fixed  point,  antagonizing  the  gluteus  maxi- 
mus.  Its  nerve-supply  is  from  the  anterior  crural  of  the  lumbar  plexus. 

Origin. — (i)  The  upper  surface  of  the  ala  of  the  sacrum  ;  (2)  the  front  of  the 
ilio-lumbar,  lumbo-sacral,  and  anterior  sacro-iliac  ligaments  ;  (3)  the  upper  and 
outer  half  of  the  venter  of  the  ilium  ;  (4)  the  origin  of  the  upper  tendon  of  the 
rectus  femoris  and  the  ilio-femoral  ligament  near  the  anterior  inferior  spine  of 
the  ilium. 

The  Psoas  Parvus. — Usually  absent.  Inserted  into  the  ilio-pectineal  line. 
Origin :  Side  of  twelfth  thoracic  and  first  lumbar  and  disc  of  cartilage  between 


...    Transversalis 


-!••   Internal  oblique 


"•  External  oblique 


Sacro-lumbalis 


LatiBSimus  dorsi 


Quadratus  lumborum 


FlG.   1C 


Longissiinus  dorsi 
Psoas  magnus 

. — ARRANGEMENTS  OF  LUMBAR  APONEUROSIS  AT  LEVEL  OF  THIRD  LUMBAR  VERTEBRA. 


the  two.  Synergistic  to  psoas  magnus.  Its  nerve-supply  is  from  the  first  nerve 
of  the  lumbar  plexus. 

The  obturator  internus  may  now  be  removed  from  its  origin.  (Fig.  196.) 
Trace  the  same  through  the  lesser  sacro-sciatic  foramen.  Study  the  origin  from 
the  marein  of  the  obturator  foramen,  the  obturator  membrane,  and  the  inner 

o 

surface  of  the  body  of  the  ischium.  Its  nerve-supply  is  from  the  first  and  second 
nerves  of  the  sacral  plexus  ;  it  passes  through  the  lesser  sacro-sciatic  foramen. 

Obturator  Externus. — Detach  the  muscle  from  the  bony  margin  of  the 
obturator  foramen  ;  from  the  obturator  membrane.  It^s  inserted  into  the  digital 
or  trochanteric  fossa.  It  is  supplied  by  the  obturator  nerve.  Now  you  can  see 
and  study  the  obturator  membrane.  See  the  obturator  nerve  coming  through  a 
notch  on  under  surface  of  the  horizontal  ramus  of  the  os  pubis. 

Locate  on  tlie  sacrum  (Fig.  199)  :  (i)  The  bodies  ;  (2)  the  anterior  sacral  fora- 
mina ;  (3)  the  transverse  lines  ;  (4)  the  ala  or  wing  ;  (5)  the  sacro-coccygeal  artic- 
ulation ;  (6)  the  origin  of  the  pyriformis  ;  (7)  the  grooves  leading  to  the  foramina. 

The   pyriformis   arises   from    the   anterior  surface  of  the  sacrum   by  three 


290 


PRACTICAL  ANATOMY. 


digitations.      (Fig.   199.)     It  leaves  the  pelvis  by  the  greater  sacro-sciatic  fora- 
men, dividing  this  into  an  upper  and  a  lower  compartment,  and  is  inserted  into 


Fyriformi* 


TUBEROSITY 


CoocygeuB 


Coccygeus 


Levator  Ani 


FIG.  199. — THE  SACRUM  AND  G><  c  Y\.     (Anterior  view. \ 


SACi;rs: 


Pyriformis 


COCCYX 


Levator   ani     (divided 
below  the '  white  line ') 


Space  for  obturator 
internus 


RECTUM 
PROSTATE 

8YMPHYSIS 


agt,  for  gh 
vessels  and  mrrc 


Pyriformis 

1'iixfiti/i'  fur  xcitilic 
mil!  /mdif  vessel* 
nni!  nerve 

ISCHIAL  SPINE 

Coecygeus 
Cellular  interval 
Levator  ani 


Capsule  of  prostate, 
and  pubo-prostatio 
ligaments 


1  ic.   zoo. — MUSCLES  OF  THE  FLOOR  OK  TIIK  PELVIS. 


the    upper   border  of  the  greater  trocliantcr.      It   is    an  external   rotator  of  th< 
thigh.      Its  iicn-c-sitfiply  is  from  the  sacral  plexus. 

The  COCCygeus  extends  from  the  spine  of  the  ischium  to  the  anterior  snrfaa 


THE   PELVIS. 


291 


and  side  of  the  coccyx.  It  separates  two  intermuscular  cellular  spaces — (i)  one 
between  itself  and  the  pyriformis,  and  (2)  one  between  itself  and  the  levator  ani. 
(Figs.  199  and  200.)  Its  nerve- supply  comes  from  the  coccygeal  plexus. 

The  levator  ani  (Fig.  200)  arises  from  the  back  of  the  pubic  bone  and  from 
the  inner  surface  of  the  ischial  spine.  Between  these  two  points  it  arises  from 
the  white  line.  The  muscle  has  a  triple  insertion  :  (i)  Into  the  tip  of  the  coccyx  ; 
(2)  into  the  central  point  of  the  perineum  ;  (3)  into  the  rectum.  In  the  female 
the  anterior  fibres  are  inserted  into  the  side  of  the  vagina.  Function :  It  draws 
the  coccyx  forward,  elevates  the  floor  of  the  pelvis,  and  aids  in  compressing  the 
pelvic  viscera. 

The  pelvic  white  line  is  formed  by  a  delamination  of  the  obturator  fascia. 
It  extends  from  the  spine  of  the  ischium  to  the  pubic  bone.  (Fig.  200.)  It 
gives  partial  origin  to  the  levator  ani  muscle. 


FEMALE  GENERATIVE  ORGANS. 

Now  thoroughly  cleanse  the  pelvis  and  study  the  internal  organs  of  genera- 
tion of  the  female  as  follows  : 

1 .  Observe  in  front  of  the   uterus,  the   bladder,  partially  covered  by  perito- 
neum.     In  front   of  the  bladder  you   will  see  a  cellular   space    called    Retzius' 
space. 

2.  Pull  the  uterus  to  one  side   and  study  the  relation  of  the  following  struc- 


AMPUUA  OF  FALLOPIAN  TUBE 


FALLOPIAN  TUBE 

EXTERNAL  ANGLE  OF  UTERUS 


FIMBRIATED  EXTREMITY  OF  TUBE  Hound  ligament 

FIMBRIA  OVARIOA  Ligament  of  ovary 

Anterior  peritoneal  lamina 

FIG.   201. — THE  BROAD  LIGAMENT  AND  ITS  CONTENTS,  SEKN  KROM  THE  FRONT.     (After  Sappey). 


tures  :   (i)  The    round  ligament  of  the    uterus;    (2)  the   ligament   of  tJic  ovary; 
(3)  the  Fallopian  tube,  or  oviduct. 

As  you  pull  the  uterus  to  the  opposite  side,  you  will  notice  these  three 
structures  dispersing  to  different  parts  from  the  angle  of  the  uterus.  Trace 
them  out,  remembering  they  are  all  between  the  two  layers  of  the  broad  liga- 
ment (Fig.  201),  as  follows  :  (i)  The  round  ligament  to  the  internal  abdominal 
ring,  on  the  outer  side  of  the  deep  epigastric  artery,  down  through  the  inguinal 


292 


PR  A  CTICAL    ANA  TOM  )  . 


canal,  out  through  the  external  abdominal  ring,  to  the  labia  majora  ;  (2)  the  ovarian 
ligament  terminates  in  the  capsule  of  the  inner  end  of  the  ovary  ;  (3)  trace  the 
oviduct — /'.  e.,  the  Fallopian  tube — to  the  outer  end  of  the  capsule  of  the  ovary, 
to  which  it  is  attached  by  one  of  the  fimbriae,  called  the  ovarian  fimbria. 

3.   Locate  tJie  ureter  as  it  passes  down  over  the  brim  of  the  pelvis  ;   trace  it 


FIG.   202. — REPRESENTING  SCHEMATICALLY  THE  RELATION  OF  THE  URETER  TO  THK  BROAD 

LIGAMENT  OF  THE  UTERUS. 

A.  Peritoneum.  B.  Peritoneum  in  relation  to  bladder.  C.  Peritoneum  pushed  ahead  of  the  uterus — 
called  broad  ligament.  D.  Space  between  the  two  layers  of  broad  ligament  containing  uterus  and 
adnexa.  E.  The  ureter.  F.  Uterine  and  ovarian  vessels. 

carefully  as  it  approaches  the  posterior  surface  of  the  broad  ligament.  (Fig.  202.) 
Now,  as  it  passes  under,  cut  a  hole  in  the  posterior  surface  of  the  broad  ligament 
and  follow  it  across  the  base  and  to  the  bladder.  Notice,  too,  that  as  you  take 
hold  of  the  broad  ligament  and  lift  it  up,  the  ureter  remains  in  place.  There 
would,  seem  to  be  little  danger  of  including  this  structure  in  the  ligature  in  opera- 


UTERINE  WALL 
CAVITY  OF  BODY 


CAVITY  OF  CERVIX  WITH  ARBOR  VITA  - 


IMC.  203. — FKONTU,  SKCTION  <>i     riu    YIUCIN   UTKRUS.      (After  Sappey.) 

tions  on  the  ovary  and  tube.  As  the  ureter  lies  on  the  levntor  ani,  there  would 
be  more  danger  of  wounding  it  in  operations  on  the  ischio-rectal  fossa  than  in 
the  operation  before  mentioned.  The  ureter  remains  firmly  embedded  in  the 
deep  layer  of  subperitoncal  connective  tissue,  anil  can  not  be  raised  by  any 
ordinary  amount  of  traction  exerted  on  the  ovary,  tube,  and  broad  ligament. 


THE   PELVIS. 


293 


Cervical  branch 


Coronal  artery 


Branch.      Brandies       Branch 

I'terine    toroti/nl  to  to          EXTREMITY  OF 

branch    ligament       isthmus      ampulla    FALLOPIAN  TUBE 


\ 


Ovarian  branches 

Uterine  artery 
Internal  iliac  artery 

Vaginal  arteries 


Azygos  artery  of  vagina 
FIG.  204. — SCHEME  OF  THE  OVARIAN  AND  UTERINE  AND  VAGINAL  ARTERIES. 


POSTERIOR  SURFACE  OF  BODY  OF  UTERUS 


IT tero -ovarian  ligament 
OVARY 

FALLOPIAN  TUBE 


Broad  ligament 


FIMBRIATEO  EXTREMITY 

OF  TUBE 
FIMBRIA  OVARICA 

Lower 

part  of  broad  ligament 
OS  UTERI 

OS  EXTERNUM 

VAGINAL  WALL,  DIVIDED  AND  REFLECTED 


VAGINA,  ANTERIOR  WALL 


FIG.  205. — THE  FEMALE  ORGANS  OF  GENERATION.     (Modified  froru  Sappey. 
(Vagina  divided  and  laid  open  behind.) 


294 


PRACTICAL  ANATOMY. 


The  Ovarian  Artery  and  the  Sympathetic  Nerve. — This  artery  you  will 
see  shining  through  the  peritoneum,  passing  behind  the  ureter,  opposite  the 
bifurcation  of  the  aorta.  You  will  remember  its  origin  from  the  aorta,  below 
the  renal,  and  its  homologue,  the  spermatic.  Trace  it  down  in  this  manner  :  Lift 
the  peritoneum  up,  over  the  artery,  and  cut  the  same  with  the  scissors.  Make 
every  effort  not  to  disturb  the  artery  in  its  bed.  Trace  the  artery  now  to  the 
lateral  space,  between  the  two  folds  of  broad  ligament  (Fig.  202),  to  its  distribu- 
tion and  anastomosis,  as  shown  in  figure  204.  You  will  find  the  uterine  artery 
embedded  in  the  side  of  the  uterus,  between  the  two  folds  of  the  broad  ligament. 
Find  the  artery,  and  trace  it  out  to  its  origin  from  the  internal  iliac  artery.  (Fig. 
204.)  You  will  find  an  abundant  supply  of  sympathetic  nerves  forming  the  uterine 
plexus.  Figure  203  gives  a  frontal  section  of  the  uterus,  which  you  may  now 
imitate.  In  the  angle  of  the  uterus  find  the  opening  for  the  Fallopian  tube. 
Locate  the  os  internum  and  externum.  Figure  206  is  a  sagittal  section.  Cut 
through  the  vagina  and  study  the  utero-vaginal  junction. 

Remember  the  analysis  of  the  pelvic  plexus.  Formed  :  (i)  by  prolongation 
of  the  hypogastric  plexus  ;  (2)  by  branches  from  the  second,  third,  and  fourth 


FUNDUS 


08  INTERNUM   — -V- 


CAVITY  OF  CERVIX 

POSTERIOR  FORNIX 
POSTERIOR  LIP 


CAVITY  OF  BODY 


REFLEXION  OF  PERITONEUM 


ANTERIOR  LIP 
ANTERIOR  FORNIX 


OS  EXTERNUM 

FIG.  206. — SAGITTAL  SECTION  OF  THE  VIRGIN  Unau's.     (After  Sappey.) 

sacral  nerves  ;  (3)  by  branches  from  the  two  upper  sacral  ganglia.  Located  :  By 
the  side  of  the  rectum,  vagina,  and  uterus  in  the  female.  Distribution  :  To  all  the 
viscera  in  the  pelvis.  The  nerves  accompany  the  branches  of  the  internal  iliac 
artery.  The  nerves  proceed  from  a  plexus  on  the  artery  ;  the  plexus  proceeds 
from  a  ganglion  ;  the  ganglion  is  supported  by  the  pelvic  plexus  ;  the  pelvic  plexus 
is  in  communication  with  the  hypogastric  plexus  through  a  prolongation  of  this 
latter. 


I .  \aine  (lie  ligaments  of  tlie  uterus  you  hare  tints  far  found,  ami  explain 
tlteir  derivation. 

(i)  The  round  ligament;  (2)  one  in  front,  called  the  anterior  or  vesico- 
uterine;  (3)  one  posterior,  the  recto-uterine;  (4)  two  sacro-uterine  ;  (5)  two 
broad  ligaments.  The  round  ligament  that  in  your  dissection  you  tr.uvd 
through  the  inguinal  canal,  is  lost  in  tin-  lahia  majora  ;  it  is  homologous  to  tlu- 
spermatic  cord.  It  is  composed  of  fibrous  and  muscular  tissue  from  the  uterus. 
Thecord  N  attended  1>\  a  hood  of  peritoneum  called  the  canal  of  Nuck.  To  SC€ 


THE  PELVIS.  295 

this  canal  before  it  becomes  obliterated,  you  must  examine  female  foetuses.  The 
other  uterine  ligaments  are  of  peritoneal  origin,  and  can  and  must  be  demon- 
strated on  your  work. 

2.  From  u>/iat  source  does  the  n  terns  receive  its  blood  / 

Through  the  uterine  branch  of  the  internal  iliac  artery.  It  anastomoses 
above  with  the  ovarian  and  below  with  the  vaginal  arteries.  It  is  surrounded 
by  the  uterine  plexus  of  nerves,  from  the  pelvic  plexus.  (Fig.  204.) 

3.  Explai)i  the  rationale  of  contraction  of  adhesions  in  retroflcxions. 

In  the  dissection  of  the  peritoneum  it  was  shown  that  an  organ  previously 
invested  by  peritoneum,  may  lose  its  peritoneum,  in  parte  or  in  toto,  by  loss  of 
the  blood-supply  at  a  given  point,  by  pressure.  .(Fig.  170.)  The  uterus  bears  the 
same  relation  to  its  investing  peritoneum  that  the  colon  does  to  its  own.  Things 
equal  to  the  same  thing  are  equal  to  each  other  ;  the  two  results  are  identically 
the  same.  The  colon,  by  loss  of  its  specific  epithelial  element,  becomes  physio- 
logically adherent  to  the  parietes,  because  this  adhesion  will  cause  no  ulterior 
hindrance  to  the  function  of  the  colon.  The  uterus,  however,  contracts  patho- 
logical adhesions,  because  the  uterus  can  not,  in  the  position  these  adhesions 
entail,  discharge  its  function  physiologically. 

4.  Does  the  uterus  undergo  important  structural  changes  / 

Anatomical  structure  is  always  the  correlative  of  function.  Not  only  the 
uterus,  but  all  its  appendages,  obey  this  law  of  philosophy — correlation  ot 
structure  and  function.  In  the  pre-puberty  state,  the  female  genitalia  are  pro- 
ducts of  growth,  not  of  development ;  in  the  post-puberty  state  they  are  the  pro- 
ducts of  both  growth  and  development.  During  menstruation  and  pregnancy, 
the  uterus  and  its  appendages  become  relatively  changed  in  size  according  to 
function.  At  the  menopause,  with  cessation  of  functional  activity,  these  parts 
become  metamorphosed,  in  a  retrograde  manner. 

5.  Explain  the  anatomical  factors  in  the  production  of  ovarian,  uterine,  rectal, 
and  uretliro-vcsical  reflexes — in  short,  of  pelvic  reflexes  in  general  and  particular. 

This  belongs  to  physiology,  to  which  chair  I  refer  a  detailed  answer  ;  but 
in  order  to  make  you  familiar  with  the  anatomical  elements  involved  in  reflex 
phenomena,  I  know  you  will  pardon  just  enough  physiological  digression  to 
keep  up  an  interest  in  the  anatomical  regions  involved. 

Reflexes  are  of  two  general  kinds  :  (i)  simple  ;  (2)  complex.  The  simplicity 
of  the  one  depends  on  the  positive  conductivity  of  somatic  nerves  and  the  sim- 
plicity of  the  factors  involved. 

The  complexity  "of  the  other  depends  on  the  negative  conductivity  of  sympa- 
thetic nerves  and  the  complexity  of  the  factors  involved. 

The  factors  involved  are:  (i)  A  nerve-center  capable  of  receiving  sensory 
impressions  from  sentient  areas,  and  capable  of  originating  motor  impulses  ; 
(2)  connecting  media  between  the  center  and  the  sentient  area  capable  of  trans- 
mitting impressions  of  both  sensation  and  motion. 

Somatic  nerves  are  those  that  supply  the  body-wall  ;  they  are  usually  called 
spinal  and  cranial.  Those  nerves  are  called  sympathetic  that  are  set  aside 
principally  for  the  regulation  and  movement  of  the  viscera.  They  are  the  visceral 
branches  of  the  spinal  nerves.  The  former  transmit  pain  and  motion  violently, 
rapidly,  positively  ;  the  latter  slowly,  slight  in  degree,  negatively,  compared  to 
the  same  in  somatic  areas.  (See  page  264,  et  scq.} 


Law  of  Projectiles. — In  addition  to  the  central  and  peripheral  factors,  and 
their  motor  and  sensory  communicating  media,  we  must  be  mindful  of  the  law  of 


296  PRACTICAL  A  A' ATOMY. 

projectiles.  The  nerves  to  and  from  the  brain  are  media  by  which  the  impres- 
sions travel.  These  impressions,  then,  and  the  nerves  by  which  they  travel,  are 
projectiles,  and  are  amenable  to  the  law  of  philosophy  governing  all  projectiles  : 
(i)  A  projectile  follows  the  line  of  least  resistance  ;  (2)  a  projectile  follows  the 
point  of  greatest  traction  ;  (3)  a  projectile  may  follow  the  resultant  of  these  two 
— /.  e.,  the  line  of  greatest  traction  and  the  point  of  least  resistance. 

Anatomical  factors  determining  the  above  are  simply  the  amount  and  kind 
of  nerve  distribution  at  the  locality  whence  the  reflex  proceeds.  On  this  hypo- 
thesis alone  do  we  account  for  the  reference  of  both  pain  and  motion,  in  their 
logical  places,  in  simplex  reflexes.  In  figure  1 87,  a  simple  reflex,  the  logical 
place  for  the  pain  is  the  conjunctiva;  the  logical  place  for  the  motion  is  in  the 
orbicularis  palpebrarum.  Here  the  influences,  sensory  and  motor,  follow  the 
greatest  direct  nerve  distribution — over  cranial  nerves  having  maximal  ability 
to  transmit  both  sensation  and  motion.  On  this  hypothesis  do  we  account  for 
pain,  the  result  of  an  irritant, — for  example,  in  the  ovary,  rectum,  or  uterus, — not 
in  its  logical  place  in  the  organ  itself,  but  in  its  illogical  place,  far  away  in  some 
other  part  of  the  body,  where  both  reflex  pain  and  reflex  motion  may  be  the 
symptoms.  These  are  complex  reflexes  ;  still,  just  as  logical  in  every  way  and 
just  as  amenable  to  the  law  of  projectiles  as  simple  reflexes.  (Fig.  185.) 

Pain  is  diagnostically  one  of  the  most  important  subjective  symptoms.  It  is 
reported  peripherally.  You  must,  then,  have  a  thorough  knowledge  of  the 
cutaneous  and  membranous  distribution  of  somatic  nerves,  since  it  is  through 
these  nerves  that  pain  from  every  organ  in  the  body  may  make  its  demurrer.  The 
steps,  then,  anatomically,  in  tracing  pain  for  diagnostic  purposes  are  : 

1 .  What  cutaneous  or  sensory  nerves  supply  the  part  ? 

2.  Of  what  mixed  nerve  or  plexus  are  they  a  part  ? 

3.  Where  do  these  mixed  nerves  leave  the  spinal  canal  ? 

4.  Do  they  correspond  to  the  six  upper  intercostals  ? 

5.  Do  they  correspond  to  the  six  lower  intercostals  ? 

6.  Do  they  correspond  to  the  cervical  plexus  ? 

7.  Do  they  correspond  to  the  brachial  plexus  ? 

8.  Do  they  correspond  to  the  lumbar  plexus? 

9.  Do  they  correspond  to  the  sacral  plexus  ? 

10.  What  territory  of  organs  does  the  hypogastric  plexus  supply? 

1 1.  What  territory  does  the  solar  plexus  supply? 

12.  What  territory  does  the  cardiac  plexus  supply? 

Any  considerable  pain,  then,  as  previously  stated,  is  reported  by  a  somatic 
nerve.  If  this  somatic  nerve  is  the  innervation  pure  and  simple  of  the  painlul 
part  under  consideration,  then  the  pain  is  a  simple  direct  pain.  If,  however, 
as  frequently  happens,  the  somatic  nerve  is  the  medium  through  which  vast 
territories  are  made  to  suffer,  while  the  exciting  cause  is  in, some  remote  organ, 
then  this  pain  is  a  reflex  pain.  The  somatic  nerves  may  also  produce  reflex 
muscular  movements  in  the  muscles  corresponding  to  the  region  of  the  pain. 
(See  page  264.) 

The  student  can  not  become  too  well  grounded  in  the  philosophical  distribu- 
tion of  a  mixed  nerve  :  The  nerve-trunk  that  supplies  a  group  of  muscles  sup- 
plies also  the  skin  covering  those  muscles  ;  the  articulation  that  these  muscles 
move  ;  the  serous  or  synovial  membrane  in  contact  with  which  these  muscles 
may  lie.  The  six  upper  intercostal  nerves  supply,  then,  not  only  intercostal 
muscles,  but  the  pleura  as  well  ;  the  six  lower  supply  not  only  the  muscles  of 
the  abdominal  walls,  but  the  peritoneum  also.  An  organ,  then,  having  a  syi 
pathetic  nerve-supply,  may  manifest  its  pain  either  in  skin,  membranes,  or  artia 
lations,  and  still  not  transcend  the  logic  of  the  law  of  reflex  phi-nomc-mi. 


>matic 


THIGH  AND  LEG. 


DISSECTION  OF  THE  ANTERIOR  REGIONS  OF  THE  THIGH  AND 
LEG  AND  OF  THE  ADDUCTOR  REGION  OF  THE  THIGH. 

The  following  review  of  the  practical  osteological  points  on  the  bones  of 
the  lower  extremity  must  be  thoroughly  mastered  before  the  student  can  do 
intelligent  work  on  the  cadaver.  These  points  the  student  must  study  with  the 
bones  in  hand.  Simply  committing  to  memory  a  few  pages  of  technical  names, 
with  no  knowledge  of  a  practical  application  of  the  subject,  would  be  as  useless 
here  as  in  other  departments  of  science. 

The  Tibia : 

Name  the  bony  points  on  tlie  tibia  of  practical  importance  in  dissection. 

The  internal  tuberosity  has  one  articular  surface. 

The  external  tuberosity  has  two  articular  surfaces. 

The  tubercle,  into  which  the  ligamentum  patellae  is  inserted. 

The  crest,  or  anterior  border,  is  subcutaneous. 

The  internal  surface  is  three-fourths  subcutaneous. 

The  upper  two-thirds  of  the  external  surface  is  occupied  by  tibialis  anticus. 

The  popliteal  notch  transmits  the  popliteal  artery  and  vein. 

The  oblique  line  is  on  the  posterior  surface. 

The  femoral  articular  surfaces  of  the  head. 

The  internal  malleolus  of  the  tibia. 

The  astragaloid  articular  surfaces  of  the  tibia. 

The  posterior  surface  and  its  subdivisions. 

The  nutrient  canal,  directed  from  the  knee. 

How  many  articular  surfaces  has  the  tibia  ? 

It  has  six  articular  surfaces — two  femoral,  two  fibular,  and  two  astragaloid. 
The  student  must  find  these  surfaces  and  name  technically  the  articulations  they 
assist  in  forming.  (See  rule  for  forming  compound  words  in  introductory 
chapter.) 

What  can  yon  say  of  the  internal  surface  of  the  tibia  / 

It  is  subcutaneous  in  its  lower  three-fourths.  (Fig.  207.)  Its  upper  one-fourth 
is  occupied  by  the  insertions  of  the  semitendinosus  and  gracilis  muscles,  which 
are  inserted  by  tendons,  and  the  sartorius,  inserted  by  aponeurosis. 

What  important  flexor  muscle  is  inserted  into  the  posterior  part  of  tJic  internal 
tnherosity  ? 

The  tendon  of  the  semimembranosus  muscle.  It  will  be  seen  presently 
that  this  muscle  has  also  three  aponeurotic  insertions  that  have  very  important 
relations  and  functions  in  the  vicinity  of  the  knee-joint. 

Describe  the  posterior  surface  of  the  tibia. 

It  is  divided  by  two  lines — an  oblique  and  a  vertical  one — into  three  sub- 
divisions. (Fig.  208.)  One  of  the  three  surfaces  is  occupied  by  the  popliteus 
muscle ;  a  second  by  the  flexor  longus  digitorum ;  a  third  by  the  tibialis 
posticus. 

20  297 


298  PRACTICAL   ANATOMY. 

Describe  fully  the  oblique  line  of  the  tibia.     (Fig.  208.) 

It  extends  from  the  fibular  articular  surface  to  the  middle  one-third  of  the  bone, 
on  the  inner  border.  It  may  be  considered  as  possessing  three  lips — an  upper, 
a  middle,  and  a  lower.  Into  the  upper  is  inserted  the  popliteal  fascia  ;  from  the 
middle  arises  the  tibial  head  of  the  soleus  ;  from  the  lower,  the  flexor  longus 
digitorum  and  tibialis  posticus. 

Describe  the  vertical  line. 

It  extends  in  a  curved  line  downward  and  outward  to  the  middle  one-third  of 
the  outer  or  interosseous  border  of  the  tibia.  It  separates  the  surfaces  occupied 
by  the  tibialis  posticus  and  flexor  longus  digitorum  muscles.  It  also  marks  the 
location  of  the  nutrient  foramen  of  the  tibia,  proceeding,  according  to  rule,  from 
the  knee. 

Name  the  important  parts  of  the  internal  mall  coins  of  the  tibia. 

Posteriorly  are  two  grooves  for  the  tibialis  posticus  and  flexor  longus  digi- 
torum ;  one  surface  articulates  with  the  astragalus  ;  to  the  apex  is  attached  the 
internal  lateral  ligament  of  the  ankle-joint. 

The  Fibula: 

Name  the  points  on  the  fibula  of  importance  in  practical  anatomy. 

The  head,  for  insertion  of  the  biceps  tendon. 

The  styloid  process  of  the  head,  for  external  lateral  ligament. 

The  tibial  articular  surface. 

The  external  malleolus  of  the  fibula. 

The  anterior  surface  of  the  fibula. 

The  outer  surface  of  the  fibula. 

The  internal  surface  of  the  fibula. 

The  posterior  surface  of  the  fibula. 

What  is  the  importance  of  the  anterior  surface  of  the  fibula  /     (Fig.  207.) 

Its  width  is  one-fourth  of  an  inch.  It  gives  origin  to  the  extensor  proprius  or 
extensor  longus  hallucis,  the  extensor  longus  digitorum,  the  peroneus  tertius — 
i.  e.,  all  the  muscles  on  the  front  of  the  leg,  except  the  tibialis  anticus. 

What  can  you  say  about  the  external  surface  of  the  fibula  f     (Fig.  207.) 

It  gives  origin  to  and  is  occupied  by  the  peroneus  longus  and  peroneus  brevis 
the  former  occupies  the  upper  two-thirds  ;  the  latter,  the  lower  two-thirds. 

What  is  the  importance  of  the  posterior  surface  of 'the  fibula  / 

It  gives  origin  in  its  upper  one-third  to  the  fibular  head  of  the  soleus  ;  in  its 
lower  two-thirds  to  the  flexor  longus  hallucis.  (Fig.  208.) 

Give  the  importance  of  the  internal  surface  of  tJic  fibula. 

It  gives  attachment  to  the  tibialis  posticus — i.  t\,  to  the  fibular  head  of  this 
muscle. 

/  /  'hat  can  you  say  of  the  patella  ? 

It  is  the  largest  sesamoid  bone  in  the  body.  It  is  developed  in  the  common 
tendon  of  insertion  for  the  group  of  muscles  that  extend  the  leg  on  the  thigh — the 
quadriceps  extensor fcinoris.  It  has  two  articular  surfaces,  corresponding  to  tin- 
trochlear  articular  surface  of  the  femur.  The  ligamentum  patellae  is  inserted  into 
the  tubercle  of  the  tibia.  A  pad  of  fat  and  a  hursa  intervene  between  the  patella 
and  tibia,  except  at  the  insertion. 

The  Foot  and  Ankle : 

\aine  the  osteological points  of  the  foot  and  ankle  of  importance  in  dissection. 

The  posterior  surface  of  the  calcaneum. 

The  sustentaculum  tali  of  the  calcaneum. 

The  peroneal  grooves  of  the  calcaneum. 

The  inner  and  outer  tuberositics  of  the  calcaneum. 

The  cuboid  surface  of  the  calcaneum. 

The  astragaloid  surface  of  the  calcaneum. 


THIGH  AND   LEG.  299 

The  tuberosity  of  the  scaphoid  bone. 

The  cuneiform  articular  surfaces  of  the  scaphoid. 

The  medio-tarsal  articulation. 

The  base  of  the  first  metatarsal  bone. 

The  base  of  the  fifth  metatarsal  bone. 

Wliat  two  tendons  do  yon  expect  to  find  on  the  outer  surface  of  the  calcanemn  / 

The  tendons  of  the  peroneus  longus  and  brevis.  They  are  separated  by  a  little 
spine  of  bone — the  peroneal  intertendinous  spine.  Each  tendon  is  in  a  separate 
canal  here,  but  higher  up,  behind  the  outer  malleolus,  they  are  in  the  same  canal. 

How  woidd  you  describe  the  peronens  innscle  so  as  to  give  the  bony  parts  of  t/ie 
limb  due  prominence  ? 

The  peroneus  longus  arises  from  the  outer  surface  of  the  fibula  in  its  upper 
two-thirds  ;  its  tendon  passes  behind  the  external  malleolus  of  the  fibula,  with  the 
tendon  of  the  peroneus  brevis  ;  it  passes  on  the  outer  surface  of  the  calcaneum, 
in  the  inferior  peroneal  groove  ;  it  passes  through  a  groove  on  the  under  surface 
of  the  cuboid  bone  ;  it  is  tendinously  inserted  into  the  base  of  the  first  meta- 
tarsal bone,  having  traversed  an  osseo-aponeurotic  canal,  from  the  cuboid  bone  to 
its  insertion. 

Describe  the  peroneus  brevis. 

It  arises  from  the  outer  surface  of  the  fibula,  middle  one-third  ;  passes  behind 
the  external  malleolus  of  the  fibula  ;  passes  through  the  superior  peroneal  groove, 
on  the  outer  surface  of  the  calcaneum  ;  and  is  inserted  into  the  base  of  the  fifth 
metatarsal  bone. 

Name  the  grooves  through  which  the  tendon  of  the  flexor  longus  Jiallucis  passes. 

This  muscle  arises  from  the  posterior  surface  of  the  fibula,  in  its  middle  two- 
thirds.  It  passes  through  a  groove  in  the  posterior  part  of  the  tibia  (Fig.  208)  ; 
through  a  second  groove,  in  the  posterior  surface  of  the  astragalus,  one  inch 
below  the  first  groove  ;  through  a  third  groove,  on  the  under  surface  of  the  sus- 
tent'aculum  tali  of  the  os  calcis  or  calcaneum  ;  through  a  fourth  groove,  between 
the  two  sesamoid  bones,  in  the  tendons  of  the  flexor  brevis  hallucis,  at  the  meta- 
tarso-phalangeal  articulation  of  the  great  toe. 

Name  the  muscles  attached  to  t/ie  inferior  surface  of  the  os  calcis. 

The  abductor  hallucis,  abductor  minimi  digiti,  flexor  brevis  digitorum,  and 
musculus  accessorius. 

Describe  tlie  insertion  of  the  antagonistic  muscles — tibia  Us  anticus  and  tibialis 
posticus. 

The  tibialis  anticus  is  inserted  into  the  inner  surface  of  the  internal  cuneiform 
bone  and  adjacent  part  of  the  base  of  the  first  metatarsal  bone.  (Figs.  2 1 3-2 15.) 
The  tibialis  posticus  is  inserted  into  the  tuberosity  of  the  scaphoid  bone,  into  the 
sustentaculum  tali,  into  the  bases  of  the  second,  third,  and  fourth  metatarsal 
bones,  and  into  all  the  tarsal  bones  except  the  astragalus. 

How  shall  'we  recognize  and  knoiv  these  numerous  small  insertions  of  the  tibialis 
posticus  muscle  ? 

You  can  easily  trace  them  as  small,  tendinous  bands  from  the  tuberosity  of 
the  scaphoid  bone  to  all  other  insertional  points.  (Fig.  215.) 

Describe  the  importance  of  the  sustentaculum  tali. 

A  superior  surface  articulates  with  the  inner  articular  facet  of  the  astragalus  ; 
its  inferior  surface  is  grooved  and  lined  by  synovial  membrane,  for  the  transmis- 
sion of  the  tendon  of  the  flexor  longus  hallucis. 

Give  tlie  importance  of  the  superior  surface  of  the  calcaneum. 

(i)  It  gives  origin  to  the  extensor  brevis  digitorum  ;  (2)  it  articulates  with 
the  astragalus  by  two  surfaces. 

What  is  the  importance  of  the  posterior  surface  of  the  os  calcis  ? 

Into  this  surface  is  inserted  the  tendo  Achillis. 


300 


PRACTICAL  ANATOMY. 


SPINE.OF  TIBIA 


Internal  flbro-cartilage 

Coronary  ligament 

Anterior  crucial  ligament 

INNER  TUBEROSITY 

Internal  lateral  ligament 

Ligamentum  patellae 

(Quadriceps  extensor) 

Oracilis 

Sartorius 

Semitendinosua 


EXTERNAL  SURFACE  OF  TIBIA 
Tibialis  anticus 


ANTERIOR  BORDER  OR  CREST  OF  THE  TIBIA 


INTERNAL  SURFACE  OF  TIBIA 


Interosneous  membrane 


Anterior  ligament  of  ankle-joint. 


Internal  lateral  ligament 

INTERNAL  MALLEOLUS 


External  flbro-oartilage 
Capsule 

OUTER  TUBEROSITY 

Biceps  and  the 

Anterior  tibio-flbular  ligament 

External  lateral  ligament 


Extensor  longus  digitorum 


Peroneus  longus 


Peroueus  brevli 


Extensor  longus  digitorum 


PERONEAL  SURFACE  OF  FIBULA 


EXTENSOR  SURFACE  OF  FIBULA 
Extensor  proprius  hallucis 


Anterior  tibio-flbular  ligament 


•EXTERNAL  MALLEOLUS 
External  lateral  ligament 
(Anterior  fasciculus) 


FIG.  207. — Tin    1  iii   TII;IA  AM>  FiiiUi.A.     (Anterior  view.) 


THIGH  AND   LEG. 


POPLITEAL  NOTCH 


External  flbro-cartilage 

Capsule 
Posterior  crucial  ligament 

STYLOID  PROCESS 
Posterior  tibio-flbular  ligament 


Tibialis  posticus 


Flexor  lougus  hallucii 


FLEXOR  SURFACE  OF  FIBULA 


NUTRIENT  FORAMEN 


FIBULA 


Feroneus  brevis 


Posterior  tibio-flbular  ligament 

GROOVE  FOR  FLEXOR  LONGUS  HALLUCIS 

External  lateral  ligament 

(posterior  fasciculus) 

External  lateral  ligament 

(middle  1'asciculusj 


Internal  flbro-cartilage 
Capsule 

Semimembranosus 


Popliteus 


OBLIQUE  LINE 
Soleua 


POSTERIOR  SURFACE  OF  TIBIA 


Flexor  longuu  digitorum 


TIBIA 


GROOVE  FOR  T1B1ALIS  POSTICUS  AND 
FLEXOR  LONGUS  DIGITORUM 


Internal  lateral  ligament 


Posterior  ligament  of  ankle-joint 

FIG.   208. — THE  LEFT  TIBIA  AND  FIBULA.     (Posterior  view.) 


302  »       PRACTICAL   ANATOMY. 

Locate  by  limitation  tlie  medio-tarsal  joint,  and  give  the  surgical  importance 
thereof. 

Posteriorly,  it  is  limited  by  the  calcaneum  and  astragalus  ;  anteriorly,  by  the 
cuboid  and  scaphoid.  It  is  through  this  articulation  the  knife  passes  in  Chopart's 
amputation  at  the  medio-tarsal  articulation. 

Locate  by  limitation  the  tarso-metatarsal  articulation,  and  give  its  surgical 
importance. 

It  is  limited  posteriorly  by  the  cuboid  and  cuneiform  bones  ;  anteriorly,  by 
the  bases  of  the  metatarsal  bones.  It  is  through  this  articulation  Lisfranc's 
amputation  is  made. 

Locate  on  the  cadaver  :  (i)  The  crest  of  the  ilium  ;  (2)  the  anterior  iliac  spine  ; 
(3)  the  spine  of  the  pubes  ;  (4)  the  symphysis  pubis  ;  (5)  the  pubic  crest;  (6) 
the  femoral  condyles,  internal  and  external ;  (7)  the  tuberosities  of  the  tibia, 
internal  and  external ;  (8)  the  head,  neck,  and  styloids  of  the  fibula  ;  (9)  the  crest 
of  the  tibia  ;  (10)  the  subcutaneous  inner  surface  of  the  tibia  ;  (i  i)  the  inner  and 
outer  malleoli  ;  (12)  the  os  calcis  ;  (13)  the  cuboid  bone  ;  (14)  the  tuberosity  of 
the  scaphoid;  (15)  the  patella  and  ligamentum  patellae;  (16)  the  tubercle  of 
the  tibia  ;  (17)  Poupart's  ligament  or  crural  arch. 

How  to  Make  Skin  Incisions.  —  First  cut  through  the  skin  from  the 
centre  of  Poupart's  ligament  to  the  centre  of  the  second  toe,  the  incision  pass- 
ing through  the  mid-line  of  the  patella.  The  second  cut  extends  along 
Poupart's  ligament,  from  the  anterior  superior  spine  of  the  ilium  to  the  symphysis 
pubis.  The  third  cut  extends  from  one  femoral  condyle  to  the  other.  The 
fourth  cut  extends  from  the  inner  to  the  outer  malleolus.  Now  remove  the 
skin.  Always  follow  this  rule  in  removing  the  skin  :  Cut  closely  enough  to 
the  skin  to  permit  light  to  shine  through. 

THE  SUPERFICIAL  FASCIA. 

The  superficial  fascia  is  the  second  covering  of  the  body.  It  contains  a  vari- 
able amount  of  fat.  When,  as  a  result  of  starvation  or  malnutrition,  this  fat 
disappears,  the  skin  lies  closely  upon  the  deep  fascia,  and  bony  eminences  are 
numerous — in  other  words,  the  individual  is  emaciated.  This  fascia  always 
consists  of  two  layers — an  upper  layer,  containing  the  fat ;  a  deep  layer,  in  which 
are  found  the  cutaneous  vessels  and  nerves.  The  immense  fatty  mass  in  the 
superficial  fascia  is  recorded  in  the  surgical  description  of  operations  as  the 
panniculus  adiposus.  Remember  that  there  are  numerous  arteries  in  the  super- 
ficial fascia  for  the  nutrition  of  the  skin,  but  few  of  them  have  special  names. 
Collectively  they  are  known  as  superficial,  dermal,  or  cutaneous  arteries.  There 
are  also  numerous  veins  in  this  fascia.  On  account  of  their  large  size  ami 
surgical  importance,  quite  a  number  have  received  special  names — as  long  and 
short  saphenous  ;  still  here,  too,  the  rank  and  file  of  veins  are  collectively  desig- 
nated, as  are  the  arteries — viz.  :  superficial,  dermal,  or  cutaneous.  By  common 
consent,  the  word  superficial  is  used  by  anatomists  to  designate  anything  in  tlu 
superficial  fascia  ;  hence  all  arteries,  veins,  nerves,  muscles,  and  lymphatics,  ii 
this  fascia  may  properly  be  collectively  designated  superficial. 

I  laving  removed  the  skin,  according  to  directions  previously  given,  consult 
figures  209,  210,  and  21 1,  and  find  in  the  deep  layer  of  the  superficial  fascia  the 
following  cutaneous  or  superficial  structures  : 

1.  The  dorsal  venous  arch  of  the  foot — arcus  dorsalis  peclis. 

2.  The  long  saphenous  vein  and  its  tributaries, 

3.  The  short  saphenous  vein  and  its  tributaries. 

4.  The  internal  and  external  femoral  cutaneous  veins. 

5.  The  superficial  epigastric  vein  and  its  tributaries. 


>n 

E 


THIGH  AND   LEG. 


3°3 


6.  The  superficial  circumflex  iliac  vein  and  tributaries. 

7.  The  superficial  external  pudic  vein. 

8.  The  spermatic  cord,  just  below  the  pubic  spine.     (Fig.  211.) 

9.  Superficial  inguinal  and  femoral  lymphatic  glands.     (Fig.  210.) 

10.  The  long  saphenous  nerve,  with  a  vein  of  like  name.  (Figs.  209  and  210.) 

1 1.  The  short  saphenous  nerve  and  vein  (posteriorly). 

12.  The  cutaneous  branch  of  the  musculo-cutaneous  nerve.     (Fig.  209.) 

13.  The  internal,  middle,  and  external  cutaneous  nerves.     (Fig.  209.) 

14.  The  ilio-hypogastric  and  genito-crural  nerves.      (Fig.  209.) 

15.  The   patellar  plexus,  formed  by  the  union  of  cutaneous  branches,  from 


EXTERNAL 
CUTA- 
NEOUS 


ILIO- 
INGUINAL 


TWIG 
FROM  IN- 
TERNAL 
CUTA- 
NEOUS 


INTERNAL 
CUTA- 
NEOUS 


PATELLAR 
BRANCH 
OF  LONG 
SAPHE- 
NOUS 

LONG 
SAPHE- 
NOUS 


ANTERIOR 
TIBIAL 


GENITO- 
CRURAL 


MIDDLE 
CUTA- 
NEOUS 


CUTA- 
NEOUS 
BRANCH  OF 
EXTERNAL 
POPLITEAL 


MUSCULO- 
CUTA- 
NEOUS 

SHORT 
SAPHE- 
NOUS 


FIG.  209. — DISTRIBUTION  OF  CUTANEOUS  NERVES  ON  THE  ANTERIOR  ASPECT  OF  THE  INFERIOR 

EXTREMITY. 


the  internal,  middle,  external  cutaneous  nerves,  and  a  branch  from  the  long 
saphenous  and  obturator  to  supply  the  skin  over  the  insertion  of  the  extensor 
muscles  of  the  leg,  according  to  Hilton's  /aw.  (Fig.  211.) 

1 6.  The   subsartorial   plexus,  formed  by  branches  from    the  obturator,  long 
saphenous,  and  internal  cutaneous  nerves,  to  supply  the  skin  over  the  insertion  of 
the  adductors,  according  to  Hilton's  lazv. 

17.  The   prepatellar  bursa,    found  in   the    superficial    fascia  in   front  of  the 
patella. 

Dorsal  Arch  (Fig.  210.) — How  Formed. — This  arch  is  seen  on  the  dorsum  of 
the  foot  about  one  inch  behind  the  clefts  of  the  toes.  It  is  formed  by  the  conflu- 
ence of  the  veins  from  the  skin  of  the  toes.  It  lies  upon  the  cutaneous  nerves 


PRACTICAL   ANATOMY. 


Superficial  lymphatics  from 
lateral  VOU  vf  <th<lvnirn 


Superficial  epigastric  vein 


Lymphatics  from  penis  and 

scrotum 
Common  femoral  vein 


Superficial  femoral  lymphatic  

glands 
Superficial  external  pudic  vein  — 


Internal  femoral  cutaneous  vei 


Long  saphenous  vein 


lower  and  anterior  walls 
of  abdomen 


INTERNAL  MALLEOLUS 
Dorsal  venous  arch 


FIG.  210.— THE  SUI-KKHI  IAI    VKINS  AND    I.VMI-MA  IK  s  OK  THE  Lewi  K   l.i 


THIGH  AND   LEG. 


3°5 


of  the  dorsum  of  the  foot.  It  has  two  ends,  called  inner  and  outer.  This  vein 
should  be  studied  on  your  own  feet  in  this  simple  way  :  Tie  a  bandage  very 
tightly  around  your  leg  eight  inches  below  the  knee.  The  pressure  will  retard 
the  return  circulation  and  make  all  the  superficial  veins  stand  out. 

Long  Saphenous  Vein. — This  is  the  largest  and  longest  superficial  vein  in 
the  body.  It  is  in  the  deep  layer  of  the  superficial  fascia.  It  is  attended  by  the 
long  saphenous  nerve  below  the  knee.  It  begins  at  the  inner  end  of  the  dorsal 
arch  of  the  foot  (arcns  dorsalis  pedis),  passes  in  front  of  the  internal  malleolus, 
behind  the  inner  tuberosity  of  the  tibia  and  the  inner  condyle  of  the  femur,  and 


Poupart's  ligament 

EXTERNAL  CUTANEOUS  NERVE 
MIDDLE  CUTANEOUS  NERVE 
OUTER  DIVISION  OF  INTERNAL 
CUTANEOUS  NERVE 


MIDDLE  CUTANEOUS  NERVE 
BRANCH  TO  SARTORIUS 

EXTERNAL  CUTANEOUS  NERVE 


SUBSARTORIAL  PLEXUS 
OUTER  DIVISION  OF  INTERNAL 
CUTANEO  US  NER  VE 


OUTER  DIVISION  OF  INTERNAL 
CUT  A  NEO  US  NER  VE 


MIDDLE  CUTANEOUS  NERVE 


Superficial  branches  of  femoral 

artery 

Femoral  artery 
Femoral  vein 

INNER  DIVISION  OF  INTERNAL 
CUTANEO  US  NER  VE 


Saphena  vein 

INNER  DIVISION  OF  INTERNAL 
CUTANEOUS  NERVE 

CUTANEOUS  BRANCH  OF 
OBTURATOR  NERVE 


INNER  DIVISION  OF  INTERNAL 
CUTANEOUS  NERVE 


PATELLAR  BRANCH  OF  LONG 
SAPHENA 


LONG  OR  INTERNAL  SAPHENOUS 
NERVE 


FIG.  211. — SUPERFICIAL  DISSECTION  OF  THE  FRONT  OF  THE  THIGH. 
(Hirschfeld  and  Leveille.) 


opens  into  the  common  femoral  vein,  passing  through  the  saphenous  opening  in 
the  fascia  lata.  This  vein  is  ligated  or  obliterated  in  the  radical  operation  for 
varicose  veins  of  the  lower  extremity.  (Fig.  210.) 

The  Short  Saphenous  Vein. — This  begins  at  the  outer  end  ot  the  dorsal 
arch  of  the  foot,  passes  behind  the  external  malleolus  of  the  fibula,  soon  gains 
the  posterior  mid-line  of  the  leg,  passes  between  the  two  heads  of  the  gastroc- 
nemius,  and  opens  into  the  popliteal  vein.  This  vein  is  attended  by  the  short 
saphenous  nerve. 

The  Long  Saphenous  Nerve. — This  is  the  longest  cutaneous  nerve  in  the 
body.  It  is  a  branch  of  the  anterior  crural  or  femoral  nerve.  It  is  in  Scarpa's 


306  PRACTICAL   ANATOMY. 

triangle  and  Hunter's  canal.  It  becomes  cutaneous,  by  piercing  the  deep  fascia, 
two  inches  below  the  knee,  between  the  gracilis  and  sartorius  muscles.  It  joins 
company  at  this  place  with  the  vein  of  like  name,  and  is  distributed  to  the  skin 
of  the  inner  side  of  the  leg,  foot,  and  great  toe.  This  nerve  has  its  extensive 
distribution  below  the  knee,  to  supply  the  fullest  insertion  of  the  sartorius 
muscle  and  thereby  verify  Hilton's  law. 

The  Short  Saphenous  Nerve. — This  nerve  has  a  double  formation :  a 
branch  from  the  internal  popliteal,  called  the  coninninicans  tibialis,  joins  a  branch 
from  the  external  popliteal,  called  the  coninninicans  filmlaris,  to  form  this  nerve. 
This  union  may  take  place  high  or  low.  The  nerve  accompanies  a  vein  of  like 
name,  and  is  distributed  to  the  skin  on  the  posterior  part  of  the  leg  and  the  outer 
part  of  the  foot  and  little  toe. 

The  Cutaneous  Branch  of  the  Musculo-cutaneous  Nerve  (Fig.  209). — 
This  is  a  branch  of  the  external  popliteal  nerve.  The  cutaneous  branches  are 
distributed  to  the  dorsum  of  the  foot.  The  muscular  branches  of  this  nerve 
supply  the  peronei  muscles.  Anastomosis  takes  place  between  these  cutaneous 
branches  and  also  between  the  plantar  nerves  on  the  bottom  of  the  foot,  forming 
the  general  cutaneous  pedal  anastomosis. 

The  middle  cutaneous  nerve,  a  branch  of  the  anterior  crural,  is  usually  found 
as  two  parallel  branches,  one  of  which  crosses  the  sartorius,  the  other  of  which 
pierces  the  muscle.  They  end  in  the  patellar  plexus,  having  supplied  the  skin 
on  the  front  of  the  thigh.  (Fig.  211.) 

The  internal  cutaneous  nerve,  a  branch  of  the  anterior  crural,  supplies  the  skin 
of  the  inner  part  of  the  thigh  ;  supplies  the  skin  over  the  primary  insertion  of  the 
sartorius ;  assists  the  obturator  in  forming  the  subsartorial  plexus,  and  ends  in 
the  patellar  plexus.  (Fig.  211.) 

What  is  to  be  understood  by  the  primary  insertion  of  the  sartorius  ? 

The  insertion  of  the  muscle  into  the  upper  and  inner  one-third  of  the  tibia. 
(Fig.  207.)  The  secondary  insertion  of  the  muscle  is  coextensive  with  the  perios- 
teum of  the  inner  surface  of  the  tibia  ;  hence  to  carry  out  Hilton's  law,  the  long 
saphenous  branch  of  the  anterior  crural  nerve  has  its  distribution  below  the  knee. 

How  do  structures  become  cutaneous  / 

Cutaneous  nerves  become  cutaneous  by  piercing  the  deep  fascia.  The  ho 
through  which  the  nerve  comes  is  called  an  opening,  and  takes  the  technical  name 
of  the  structure  transmitted.  Where  several  structures  pass  through  one  open- 
ing, the  largest  structure  lends  its  name  to  the  opening.  Cutaneous  structures 
piercing  the  deep  fascia  are  centrifugal  and  centripetal.  The  former,  as  nerves 
and  arteries,  have  their  origin  below  the  deep  fascia  and  their  explosion  in  the 
skin  beyond  ;  the  latter,  as  veins  and  lymphatics,  are  made  up  in  the  skin,  an 
having  collected  all  their  tributaries,  pass  through  the  deep  fascia,  to  beco 
themselves  tributary  to  deep  vessels  or  glands. 

How  dissect  the  cutaneous  nerves  of  tlie  t/iig/i  / 

There  are   two  procedures,  both   of  which   must  be   closely  followed  :  ( 
Locate  in  figure  209  the   opening  where  a  given  nerve  comes  through  ;  the 
with   your  forceps,  plow  through   the  fat  in   the   long  axis   of  the   limb,  alwa 
downward — never  from  side  to  side — until  you  find  the  emergence  of  the  nor 
The  location  of  these  openings  is  never  constant ;  they  may  vary  several  inches 
in  any  two  cases.     After  having  found  the  nerve,  then  trace  the  same  out  to  i 
several  branches.      (2)  We  trace  out  the  cutaneous  nerves  of  the  thigh  by  loca 
ing  and  lifting  up,  on  the  finger,  the  main   trunk    of  the  anterior  crural    nerv< 
This  nerve  is  found  under  Ponpart's  ligament,  beneath  the  deep  fascia,  in  a  groov 
between   the  iliacus  and  psoas  magnus  muscles.      The  nerve  once  on  the  finger, 
and    on    the    stretch,   now  plow  downward    with    the    forceps — never  with    the 
scalpel — in  the  direction  of  the  branches   given   off.       In  this  way  you  can  find 


THIGH  AND   LEG.  307 

every  branch  of  this  nerve.  Now,  as  the  anterior  crural  gives  off  the  internal 
and  middle  cutaneous  nerves,  it  yet  remains  for  us  to  find  the  external  cutaneous 
nerve. 

The  External  Cutaneous  Nerve. — This  is  a  branch  of  the  lumbar  plexus. 
You  find  its  main  trunk  by  cutting  through  the  deep  fascia  just  below  the 
anterior  superior  iliac  spine.  Its  branches  are  to  be  traced  out  in  a  manner 
similar  to  the  others.  The  cutaneous  nerves  of  the  anterior  region  of  the  thigh, 
above  referred  to,  become  cutaneous,  in  average,  at  the  junction  of  the  upper  and 
middle  one-third  of  the  thigh.  They  divide  into  many  branches  each,  and 
collectively  supply  with  sensation  the  front,  outer  .and  inner  parts  of  the  thigh, 
as  far  as  the  knee.  At  this  place  they  all  communicate  to  form  the  plexus 
patellae,  above  described. 

The  student  should  remember  that  while  the  external  cutaneous  nerve  is 
usually  given  in  the  text-books  as  a  separate  nerve  of  the  lumbar  plexus,  still, 
•physiologically  and  rationally  this  nerve  must  be  considered  as  a  divorced  or 
dismembered  branch  of  the  anterior  crural  or  femoral  nerve,  for  this  reason  :  The 
nerve -trunk  that  supplies  muscles,  supplies  the  skin  over  the  muscle,  even  to  the 
fullest  insertion.  Now,  the  anterior  crural  nerve  supplies  the  extensor  group  of 
muscles  on  the  anterior  and  outer  part  of  the  thigh,  hence  the  external  cutane- 
ous belongs  philosophically  to  the  anterior  crural  nerve,  being  divorced  therefrom. 
Such  cases  will  frequently  be  met.  The  small  sciatic  is  the  divorced  cutaneous 
part  of  the  great  sciatic  nerve. 

The  spermatic  cord  must  be  noticed  in  this  section,  on  account  of  its 
important  relation  to  two  nerves  and  two  arteries.  You  will  find  the  spermatic 
cord  emerging  from  the  inguinal  canal,  by  the  external  abdominal  ring  (Fig.  163). 
From  this  time  on  it  is  a  cutaneous  structure,  because  it  is  in  the  superficial 
fascia.  With  your  scissors  trace  the  cord  into  the  scrotum,  by  cutting  through 
the  skin  and  superficial  fascia.  On  the  front  of  the  cord  you  will  find  a  little 
nerve,  the  ilio-inguinal  ;  behind  the  cord  you  find  the  genital  branch  of  the  genito- 
crural  nerve.  These  nerves  come  from  the  lumbar  plexus.  The  ilio-inguinal 
nerve  supplies  the  side  of  the  thigh  and  the  scrotum  ;  the  genital  branch  of  the 
genito-crural  supplies  the  cremaster  in  the  male,  and  is  lost  on  the  round  liga- 
ment in  the  female.  The  arteries  in  relation  with  the  spermatic  cord  are  the 
superficial  and  deep  external  pudics,  branches  of  the  common  femoral ;  the  former 
is  in  front  of  the  cord,  the  latter  behind  the  cord. 

THE  DEEP  FASCIA  OF  THE  THIGH  AND  LEG. 

In  figure  210  the  glistening  structure,  upon  which  the  long  saphenous  vein 
and  its  tributaries  rest,  is  the  outer  or  circumferential  part  of  the  deep  fascia  of 
the  lower  extremity.  The  internal  or  central  part  of  the  deep  fascia  is,  conse- 
quently, surrounded  by  the  external.  In  looking  at  a  well-filled  comb  of  honey, 
you  see  only  a  small  part  of  the  honey-comb — the  outside  limiting  part.  If, 
however,  you  extract  the  honey,  then  you  can  see  and  examine  the  interior  cel- 
lular arrangements  ;  in  other  words,  you  can  examine  the  internal  divisions  of 
the  connective  tissue  or  deep  fascia  of  the  honey-comb.  It  is  just  so  in  examin- 
ing the  internal  parts  of  the  deep  fascia  of  the  thigh  or  of  any  organ  of  the  body. 
The  deep  part  of  the  deep  fascia  corresponds  to  the  cellular-tissue  spaces  of  the 
honey-comb.  The  spaces  are  occupied,  not  by  one  substance,  but  by  many. 
Muscles,  vessels,  bone,  nerves,  fat,  glands,  and  all  the  compounds  which  make 
up  the  limb  occupy  large  spaces,  just  as  effectually  shut  off  from  one  another  as 
is  the  honey  in  one  cell  separated  from  that  in  another  in  the  comb. 

Physiological  division  of  labor  and  differential  assimilation  cause  grouping  of 
like  compounds.  This  grouping  of  muscles  takes  place  on  the  physiological 


308  PRACTICAL  ANATOMY. 

basis  of  antagonism.  Flexors  oppose  extensors  ;  adductors  oppose  abductors  ; 
pronators  oppose  supinators  ;  levators  oppose  depressors.  Nerves  that  inner- 
vate and  vessels  that  feed  them  are  as  truly  antagonistic  as  are  the  muscles. 

The  general/ /aw  of  antagonism  is  this:  equality  in  length,  strength,  blood, 
nerve,  and  fascial  environment.  Antagonistic  groups  of  muscles  are  separated 
from  each  other  by  deep  fascia,  called  septa.  A  group  of  muscles  acting  in 
unison,  as  the  extensors  or  flexors  of  the  leg,  is  called  a  musculature.  Adjacent 
musculatures  are  separated  from  each  other  by  deep  fascia,  called  septa.  The 
individual  muscles,  of  which  groups  are  composed,  are  also  separated  by  deep 
fascia.  Bone  is  surrounded  by  deep  fascia,  called  periosteum  ;  articulations  are 
held  in  place  by  deep  fascia,  called  capsular  ligament.  Vessels  and  nerves  receive 
their  sheath,  and  glands  their  capsules  from  deep  fascia — i.  t\,  from  the  internal 
division  of  the  same. 

Minor  Details. — With  this  understanding  of  the  general  distribution  of  the 
deep  fascia  of  the  thigh,  consider  some  of  the  minor  details  : 

1.  One  characteristic  of  deep  fascia  is  the  presence  of  openings  in  the  outer 
or  circumferential  portion,  for  the  transmission  of  both  centripetal  and  centrifugal 
cutaneous  vessels  and  nerves ;   in  the  central  or  septal  portions  for  the  trans- 
mission of  those  branches  of  antagonistic  vessels  and  nerves,  called  communi- 
cating   and    anastomotic,   which    preserve    a    physiological    balance    of   power. 
Instance,   the  perforating  branches  of  the   profunda    reaching  the    hamstrings, 
and   the  communications  between  the  anterior  crural,  obturator,  and  great  sciatic 
nerves. 

2.  Deep  fascia  is  not  uniform  in  tldckness.     As  structure  is  the  correlative  of 
function,  those  parts  subjected  to  the  greatest  degree  of  tension  and  use  must 
become  thick  and  strong  in  comparison  with  less  used  parts. 

3.  Deep  fascia  of  the  leg  and  thigh  receives  in  some  localities  special  names, 
founded  on  no  rational  or  logical  ground,  but  which  are  perpetuated  in  anatomy 
and  surgery,  and  revered,  as  Egypt  points  to  her  ruins.     The  special  names  for 
the  deep  fascia  of  the  lower  extremity  are  these  :   (i)  The  fascia  la  fa,  on  the 
upper  front   part  of  the  thigh  ;   (2)  the  ilio-tibial  band,  on   the  outer  side  of  the 
thigh  ;  (3)    the  popliteal  fascia,   covering  the    popliteal    space  ;   (4)  the  internal 
annular  ligament,  between  the  os  calcis  and  internal  malleolus  ;   (5)  the  external 
annular  ligament,  between  the  os  calcis  and  external  malleolus  ;   (6)  the  anterior 
annular  ligament,  between  the  malleoli ;   (7)  the  dorsal  fascia,  on  the  back  of  the 
foot  ;   (8)  the  plantar  fascia  on  the  sole  of  the  foot  ;  (9)  the  ligamcnta  vaginalcs 
as  sheaths  for  the  flexor  tendons  of  the  toes;    (10)   the    vincula,    as    interter 
dinous  slips  ;    (i  i)  the  various  intermuscular  septa. 

4.  Deep  Fascia  Gives  Origin  and  Insertion  to  Muscles. — This  fact  is  often  IK 
fully    appreciated    by    the    student.      Instance,  the    -rastus    interims   and    rastns 
cxtcrnus,  the  muscles  on  the  anterior  part  of  the  tibia  andjftfat/a.      Be  ever  ready 
to  see  deep  fascia  giving  origin  or  insertion  to  muscles.       The  glutens  maximus 
has  one-of  its  insertionsjnto  the  deep  fascia  ;  the  ilio-tibial  band  is  in  reality  only 
the  insertion  of  the  tensor  vagina;  femoris,  by  aponeurosis. 

5.  Sn/x/irisions  of  fascia  lata  are  :  (i)  the  iliac  and  (2)  pubic  portions.     These 
are  separated  from  each  other  by  a  large  opening — the  saphenous.     The  iliac  or 
anterior  portion  is  attached  to  the  crest  of  the  ilium,  to  the  whole  of  Poupntt's 
ligament.      The  pubic  or  posterior  part  covers  the  pcctineus  muscle  and  gracilis  ; 
is  continuous  with  the  femoral  sheath  behind  the  femoral  vessels. 

Attachments  of  Ar/>  I'\rscin. — Deep  fascia  is  continuous  with  periosteum  at 
subcut.HH-oiis  areas.  These  are  called  the  attachments.  Tin-  deep  fascial  attach- 
ments of  the  lower  limb  are  as  follows.  In  the  region  of  the  hip  :  (i)  To  crest  ot 
ilium  ;  (2)  to  pubic  spine  and  body  ;  (3)  to  ischii. -pubic  ramus  ;  (4)  to  the  tubcr- 
usity  of  ischium  ;  (5)  to  sacrum  and  coccyx.  In  the  knee  region,  demonstrate 


THIGH  AND   LEG. 


3°9 


its  attachment  to  :  (i)  The  patella  ;  (2)  the  tuberosities  ;  (3)  the  condyles  ;  (4) 
the  crest  and  inner  surface  of  the  tibia.  In  the  ankle  region,  see  its  attachment : 
(i)  To  the  os  calcis  ;  (2)  to  the  malleoli  ;  (3)  to  the  tuberosity  of  the  scaphoid 
bone  and  numerous  other  places. 

Saphenous  Opening. — This  is  the  largest  opening  in  the  deep  fascia.  It  is 
situated  between  the  iliac  and  pubic  portions  of  the  fascia  lata.  Behind  it,  or  on  its 
floor,  is  the  femoral  sheath,  containing  the  femoral  artery,  vein,  and  canal.  In 
front  of  the  opening,  forming  its  roof  or  covering,  is  the  superficial  fascia,  called 
in  this  locality,  the  cribriform  fascia.  The  structures  passing  through  the 
saphenous  opening  are  numerous  :  the  long  saphenous  vein  and  the  small  vessels 
given  off  from  the  common  femoral  artery  and  vein,  and  some  lymphatic  vessels. 

Cribriform  Fascia. — Just  that  part  of  the  deep  layer  of  the  superficial  fascia, 
that  covers  the  saphenous  opening,  is  called  by  this  name.  It  was  so  called  on 
account  of  the  numerous  perforations,  transmitting  the  structures  referred  to  in 
the  previous  paragraph.  The  word  "  cribriform  "  means  sieve-like. 

Importance. — Since  fascia  often  determines  the  direction  taken  by  burrowing 
pus,  or  the  course  of  a  bullet,  its  various  superficial  attachments  should  be  care- 


FIG.  212. — THE  FEMORAL  RING  AND  SAPHENOUS  OPKNING.     (After  Holden.) 

(The  arrow  is  introduced  into  the  femoral  ring.) 

i.    Crural  arch.      2.    Saphenous  opening  of  the  fascia  lata.     3.   Saphena  vein.     4.    Femoral  vein. 
5.   Gimbernat's  ligament.      6.    External  abdominal  ring.      7.    Position  of  internal  ring. 


fully  examined,  and  its  deep  ones  found  by  dissection.  The  guide  to  finding 
these  is  to  remember  that  muscles  are  arranged  in  antagonistic  groups,  and  that 
these  groups  are  called  musculatures,  and  that  these  musculatures  are  separated  by 
septa,  and  these  septa  are  attached  to  bone — i.  e.,  continuous  with  its  periosteum. 

The  Application. — Now  apply  the  principle  of  musculatures  to  the  lower  ex- 
tremity. On  the  thigh  you  will  presently  find:  (i)  An  extensor  group  of  mus- 
cles in  front ;  (2)  a  flexor  group  behind  ;  (3)  an  adductor  group  internally. 

You  will  also  find:  (i)  A  septum  between  the  extensor  group  and  flexor 
group  ;  (2)  between  the  flexor  group  and  the  adductor  group  ;  (3)  between  the 
adductor  group  and  the  extensor  group. 

Again,  below  the  knee  you  will  find  :  (i)  A  group  of  muscles  on  the  anterior 
tibio-fibular  region  ;  (2)  a  group  on  the  outer  surface  of  the  fibula  ;  (3)  two  groups 
on  the  posterior  tibio-fibular  region.  Here,  also,  you  may  demonstrate  the  rule 
that  adjacent  musculatures  are  separated  from  one  another  by  fascial  septa,  since 
here  are  strong  bands  of  fascia  separating  the  peronei  muscles  on  the  outer  sur- 
face of  the  fibula,  from  different  musculatures  both  in  front  and  behind.  Like- 
wise, on  the  back  of  the  leg,  the  superficial  group  is  separated  from  the  deep  by 
the  transverse  fascia,  and  both  these  groups  from  lateral  musculatures. 


310  PRACTICAL  ANATOMY. 


ANTERIOR  REGION  OF  LEG. 

Remove  carefully  the  deep  fascia.  (Fig.  210.)  You  have  now,  by  the  re- 
moval of  the  skin  and  superficial  fascia,  exposed  the  deep  fascia  covering  all  the 
muscles  on  the  anterior  and  outer  regions  of  the  leg  (Fig.  213): 

1.  The  cutaneous  branch  of  the  musculo-cutaneous  nerve. 

2.  The  tibialis  anticus  and  the  tuberosity  of  scaphoid  bone. 

3.  The  extensor  proprius  hallucis  muscle. 

4.  The  extensor  longus  digitorum  muscle. 

5.  The  peroneus  tertius  muscle. 

6.  The  extensor  brevis  digitorum  muscle. 

Now  dissect  down  between  the  tibialis  anticus  and  the  extensor  proprius 
hallucis  by  cutting  through  the  deep  fascia  with  scissors  and  find  the  anterior 
tibial  nerve  and  vessels.  (Fig.  214.) 

Anterior  Tibial  Artery. — It  is  one  of  the  two  terminal  branches  of  the  pop- 
liteal artery.  It  gains  the  front  of  the  leg  by  passing  between  the  two  heads  of 
the  tibialis  posticus  and  interosseous  membrane.  It  lies  in  a  deep  groove,  bounded 
internally  by  the  tibialis  anticus  ;  externally,  by  the  extensor  longus  digitorum 
and  extensor  proprius  hallucis.  It  terminates  on  the  dorsum  of  the  foot,  continu- 
ing its  course  under  the  name  of  dorsalis  pedis.  Its  branches  are  :  (i)  The  ante- 
rior tibial  recurrent,  which  anastomoses  with  the  articular  branches  of  the  popliteal 
and  anastomotica  magna ;  (2)  posterior  tibial  recurrent,  when  present,  is  given  off 
before  the  anterior  tibial  passes  through  the  interosseous  membrane  ;  (3)  mus- 
cular branches,  which  supply  the  muscles  on  the  anterior  region  of  the  leg  (Fig. 
214) ;  (4)  malleolar  branches,  which  supply  the  ankle-joint.  On  the  back  of  the 
foot  you  cut  through  the  deep  fascia  between  the  extensor  proprius  hallucis  and 
extensor,  longus  digitorum  muscles,  to  find  the  dorsalis  pedis  artery. 

Dorsalis  Pedis  Artery. — This  is  a  continuation  of  the  anterior  tibial.  It  lies 
between  the  extensor  proprius  hallucis  and  extensor  longus  digitorum,  on  the 
dorsum  of  the  foot.  (Fig.  214.)  It  gives  off:  (i)  A  communicating  branch  to 
the  external  plantar,  by  which  the  plantar  arch  is  completed ;  (2)  a  tarsal 
artery  to  the  extensor  brevis  digitorum  and  the  tarsus  ;  (3)  the  dorsalis  hallucis 
to  the  great  toe  ;  (4)  interosseous  arteries  to  the  interosseous  spaces  and  their 
contents.  Trace  the  arteries  out  carefully  with  the  forceps.  Remember  they 
are  beneath  the  dorsal  fascia. 

Anterior  Tibial  Nerve. — It  is  a  branch  of  the  external  popliteal  nerve,  being 
given  off  with  the  musculo-cutaneous  nerve.      It  gives  off  articular  branches,  ac- 
cording to  Hilton's  law,  to  the  (i)  ankle-joint,  (2)  the  tarsal,  and  (3)  the  metatarsi 
phalangeal  joints.       It  gives  muscular  branches  to  the  extensor  brevis  digitorui 
and  to  all  the  muscles  on  the  anterior  regions  of  the  tibia  and  fibula. 

Muscles  on  Anterior  Surface  of  Fibula. — These  are  :  (i)  Extensor  proprius 
hallucis  ;  (2)  extensor  Jongus  digitorum  ;  (3)  peroneous  tertius,  the  fifth  tender 
of  the  extensor  longus  digitorum. 

Insertion  of  Extensor  Brevis  Digitorum. — This  muscle  has  four  tendon- 
The  first  is  inserted  independently  into  the  base  of  the  first  phalanx  of  the  great 
toe ;  the  remaining  three  are  inserted,  conjointly  with  the  tendons  of  the 
extensor  longus  digitorum,  into  the  bases  of  the  second  and  third  phalanges. 

Give  nen>e-supply  of  the  Jive  tmtsc/cs  nw  exposed  on  the  anterior  tibio-filntlar 
region. 

The  anterior  tibial,  a  branch  of  the  external  popliteal 

Intermuscular  Septum. — Examine  the  septum  that  separates  the  muscles 
the  anterior  surface  of  the  fibula  from  the  peronei  on  the  external  surface. 

How    to    Dissect    these     Muscles. — Tibialis    Anticus. — Cut    through    tl 


I 

us 

;: 


THIGH  AND   LEG.  311 

anterior    annular    ligament   on    the    tendon   of   the    muscle.       Now   follow    the 
tendon    to    its    insertion    into    the    internal    cuneiform    bone    and    base    of  the 


Ligamentum  patellae 


CiastrocnemiuB 


Extensor  propriua  halluei 


Dorsal  interoasei 


Peroueus  longus 


Tibiaha  anticus 


Peroneus  tertius 


Extensor  loagua  digitorum 


Peroneus  tertius 


Extensor  brevis  digitorum 


FIG.  213. — THE  MUSCLES  OF  THE  FRONT  OF  THE  LEG. 


first  metatarsal.  Then  trace  the  muscle  to  its  origin  :  (i)  the  outer  surface  of  the 
tibia,  upper  two-thirds  ;  (2)  outer  tuberosity.  Notice  the  nerve-supply  and  blood- 
sijpply. 


312 


PRACTICAL   ANATOMY. 


Extensor  Proprins  Hallucis. — Begin  at  the  end  of  the  great  toe  and  cut  down 
on   the  tendon.      Follow  it    up    through    a    separate    compartment    under    the 


Superior  internal  articular  artery  


Inferior  internal  articular  artery 


Anterior  tibial  recurrent  artery 


Anterior  tibial  artery 


Tibialis  anticus  muscle 


ANTERIOR  TIBIAL  NERVE 


Extensor  longuB  halluois 


Internal  malleolar  artery 


Anterior  annular  ligament 
Dnrsalis  pedis  artery 

Innermost  tendon  of  extensor 
brevis  digitorum 

Comitiuiiicntinij  branch 
Dorsalis  hallucis  artery 


Superior  external  articular  artery 


Inferior  external  articular  artery 


Extensor  longus  digitorum 


Extensor  longus  digitorum. 
turned  back 


Peroneus  tertiua 


Anterior peroneal  artery 


External  malleolar  artery 


Peroneus  brevis  muscle 

1\ 

»ift Extensor  brevis  digitorui 

External  tarsal  branch 

Metatanal  branch 

Dorsal  inlerosseous  artery 


FIG.   214.— THK  ANTKRIOK  TlBIAl  ARTERY,  DORSAL  ARTKRY  OF  THK  FOOT,  AM>  AMKKH 
I'KROM-.AI.  ARTKRY,  AND  TIIKIR  BRANCH  M. 

annular  ligament  to  its  origin  on  the  middle  half  of  the  anterior  surface  of  the 
fibula  and  interossrous  membrane. 

The    licensor  Longus  nigitornw. — To  dissect  this   muscle   successfully,    c  nl 


THIGH  AND  LEG.  313 

down  on   the   same   through   the  anterior   annular   ligament.     Then    use    your 
forceps  as  a  director,  and  carefully  cut  the  dorsal  fascia   over  each  of  the  four 


Teudo  Achillis 


Extensor  brevis 

digitorum 


Extensor  longue 

halluois 


Extensor  brevis 
digitorum 


Peroneus  brevis 


Peroneus  tertius 


METATARSUS 


FIRST  PHALANX 


SECOND  PHALANX 
THIRD  PHALANX 


cteusor  longus  digitorum 

FIG.  215. — THE  LEFT  FOOT.     (Dorsal  surface.) 
(Study  origin  and  insertion  of  muscles  on  this  figure  and  compare  with  your  dissection.) 


'tendons.  In  like  manner  trace  each  tendon  to  the  end  of  the  toe.  Notice  that 
each  tendon  divides  in  three  slips,  on  the  dorsal  surface  of  the  first  phalanx  ; 
that  the  middle  slip  is  inserted  into  the  base  of  the  second  phalanx  ;  that  the 

21 


3*4 


PRACTICAL  ANATOMY. 


SPINE, OF  TIBIA 


Internal  nbro-cartilage 

Coronary  ligament 

Anterior  crucial  ligament 

INNER  TUBEROSITY 

Internal  lateral  ligament 

Ligamentum  patellae 

(Quadriceps  extensor) 

Gracilis 

Sartorius 

SemitendinoauB 


EXTERNAL  SURFACE  OF  TIBIA 
Tibialis  anticus 


ANTtRIOR  BORDER  OR  CREST  OF  THE  TIBIA 


INTERNAL  SURFACE  OF  TIBIA 


InteroBBeous  membrane 


Interior  ligament  of  ankle-joint 

Internal  lateral  ligament 

INTERNAL  MALLEOLUS 


External  nbro-cartilage 
Capsule 

OUTER  TUBEROSITY 

Biceps  and  the 

Anterior  tibio-flbular  ligament 

External  lateral  ligament 


Extensor  longus  digitorum 


Peroneus  lougus 


Peroneus  brevls 


PERONEAL  SURFACE  OF  FIBULA 


EXTENSOR  SURFACE  OF  FIBULA 
Extensor  propriua  haliucis 


FIBULA 


Peroneus  tertius 


SUBCUTANEOUS  PORTION 


Anterior  tibio-flbular  ligament 


EXTERNAL  MALLEOLUS 
External  lateral  ligament 
(Anterior  fasciculus) 


FIG.  216.— THE  LEFT  THIIA  AND  FIHUI.A.     (Anterior  view.) 
(Study  origin  of  muscles  on  this  figure  and  compare  with  your  dissection.) 


THIGH  AND   LEG.  315 

two  lateral  slips  are  inserted  into  the  base  of  the  third  phalanx.  Also  notice 
the  relation  of  the  tendons  of  this  muscle  to  those  of  the  extensor  brevis  digi- 
torum.  Origin,  outer  tuberosity  of  the  tibia  and  anterior  surface  of  fibula. 

The  Peroneus  Tertius. — Find  the  insertion  of  this  muscle  in  the  base  of  the 
fifth  metatarsal.  (Fig.  215.)  Trace  it  to  the  anterior  surface  of  the  fibula,  and  notice 
that  it  blends  with  the  preceding  muscle,  a  part  of  which  it  really  is.  (Fig.  207.) 


THIGH,    ANTERIOR    AND    INTERNAL    REGIONS. 

Remove  the  deep  fascia  and  expose  the  vessels,  nerves,  and  muscles.  (Figs. 
218,  219,  and  220.) 

First  locate  the  sartorius.  (Fig.  218.)  Begin  at  the  anterior  superior  iliac  spine 
(Fig.  226)  and  expose  the  muscle  to  its  insertion  (Fig.  207)  into  the  tibia,  by  gently 
removing  all  deep  fascia.  Now  lift  up  the  muscle  from  its  bed,  taking  care  not  to 
damage  the  vessels  and  nerves  that  enter  it.  Notice  that  this  muscle  is  crossed  by 
one  and  pierced  by  another  branch  of  the  middle  cutaneous  nerve.  (Fig.  211.) 

Locate  the  gracilis  next,  on  the  inner  surface  of  the  thigh.  (Figs.  218  and 
219.)  Trace  it  from  the  descending  ramus  of  the  pubes  (Fig.  226)  to  its  inser- 
tion into  the  inner  surface  of  the  tibia  (Fig.  207),  taking  care  not  to  damage 
the  nerve  branches  of  the  obturator  that  enter  it.  This  dissecting,  by  which 
this  muscle  is  separated  from  its  fellow-muscles,  must  be  done  with  the  forceps. 

Locate  the  adductor  longus.  (Fig.  218.)  Trace  it  from  the  anterior  surface 
of  the  pubes  to  its  insertion  into  the  middle  of  the  middle  lip  of  the  linea  aspera. 
(Fig.  227.)  Divide  the  connective  tissue  between  this  muscle  and  the  pectineus. 
(Fig.  218.)  Now  cut  the  adductor  longus,  at  its  origin,  and  turn  the  same 
aside.  (Fig.  219.)  Also  cut  the  pectineus  and  turn  it  aside.  (Fig.  218.) 

Obturator  Nerve,  Anterior  Division  (Fig.  219). — This  you  will  see  lying  on 
the  adductor  brevis.  (Fig.  219.)  Take  this  nerve  up  gently,  and  follow  out  its 
branches  to  :  (i)  The  gracilis  ;  (2)  the  adductor  longus  ;  (3)  the  adductor  brevis  ;  (4) 
the  sartorius  ;  (5)  a  branch  to  the  hip-joint ;  (6)  a  branch  to  the  femoral  artery  ;  (7) 
an  occasional  branch  to  the  pectineus  muscle  ;  (8)  a  cutaneous  branch  to  assist  the 
long  saphenous  and  internal  cutaneous  in  forming  the  subsartorial  plexus. 

Obturator  Nerve,  Posterior  Division. — This  lies  on  the  adductor  magnus. 
The  adductor  brevis  muscle  then  separates  the  anterior  from  the  posterior  divi- 
sion of  the  nerve.  This  division  supplies  :  (i)  The  obturator  externus  ;  (2)  the 
adductor  magnus;  (3)  an  articular  branch  to  the  hip-joint;  (4)  an  articular 
branch  to  the  knee. 

Why  does  the  obturator  nerve  send  a  branch  to  the  knee  ? 

Because  this  nerve  supplies  the  sartorius  muscle,  a  muscle  that  moves  the 
knee-joint.  (Fig.  219.) 

Hoiv  does  the  articular  branch  from  the  obturator  nerve  enter  the  hip-joint  / 

It  passes  through  the  cotyloid  notch. 

When  the  accessory  obturator  nerve  is  present,  wliere  may  it  be  found  / 

To  the  inner  side  of  the  psoas  magnus  muscle. 

What  is  the  function  of  the  subsartorial  plexus? 

To  supply  the  skin  over  the  adductor  muscles,  and  to  exercise  a  sensory 
balance  of  power  between  the  obturator  and  anterior  crural  nerves. 

The  Anterior  Crural  Nerve  (Fig.  219). — You  will  find  the  main  trunk  of  this 
nerve  deeply  buried  in  a  space  between  the  iliacus  and  psoas  magnus.  (Fig.  197.) 
Take  this  nerve  up  on  your  finger  and  gently  follow  out  its  muscular  branches  to 
all  the  muscles  on  the  front  of  the  thigh  :  (i)  Sartorius  ;  (2)  rectus  femoris  ;  (3) 


PRACTICAL  ANATOMY. 


vastus  internus  ;  (4)  vastus  externus  ;  (5)  crureus  ;  (6)  subcrureus  ;   (7)  pectineus. 
In  tracing  these  nerves,  divide  the  connective  tissue  in  the  direction  of  the  long  axis 


EXTERNAL  POPLITEAL 

NER  VE 
RECURRENT  ARTICULAR 


MUSCULO-CUTANEO  US 


BRANCH  TO  PERONEUS 
LONG  US 


BRANCH  TO  EXTENSOR 
LONG  US  DIG  I  TO  RUM 


BRANCH  TO  PERONEUS 
B RE VIS 


MUSCULO-CUTANEO  US 


MUSCUL  O-CUTA  NEO  US 

(OI'TKIt 


S1IOR  T  SA  PHENO  US 


COLLA  TERA  I, 
BRAN<'lli-:x  OF  EX- 

/•/;/.' .V.I/,  XAP/fENOUS  • 
.I.Y/J  .vr.sYV/.o- 
CUTAM:nrs  TO  TOES 


ANTERIOR  TIBIAL 

SKI:  vi-: 


Anterior  tibial  artery 


Tibialia  anticua 


ANTERIOR  TIBIAL 
NERVE 


M  U8CULO-CUTA  Si-:<  > '  w 
(INNER  DIVISION) 


ANTERIOR  TIBIAL 

(<>r  n-:i:  />/V/ 

//•>   ItlsTIUHCTION  TO 


DIGITORUM 

ANTEIUOi:   TIlilAL 

d.\.\i:i;  i>i  VISION) 


COLLATERAL 

.v<  •///•>  or 
rxrr /.<>-(•/•/. i. \/-:o i  .s 


)  co/,/,.1  TV?/? 
BRANCHl 
MU8CULC 
TO  TOES 


l-'lC.     217. — BkAN'CHES    OF    THE    E.Vl'KKN.U.    1'ol'l.lTKAI.    NhK\l. 


of  the  ncrrc — nc-rcr  crossivise.      And  trace  it  to  the  skin  covering  the  same  by 

(i)  The  internal  cutaneous  ;  (2)  the  middle  cutaneous  ;  (3)  the  long  saphenou.< 

The  Femoral  Artery  (Fig.  223). — Get  your  finger  under  this  vessel  and  trac 


THIGH  AND    LEG. 


317 


out  its  branches.  Great  care  must  be  taken  to  divide  the  connective  tissue  binding 
the  artery  and  vein  together.  To  learn  the  branches  of  this  artery,  see  page 
320. 

Dissection  of  the  Rectus  (Fig.  2 1 8). — You  can  easily  lift  this  muscle  from  its 
b^d.      It  lies  on  the  vastus  interims.      (Fig.  220.)     Joining  the  rectus  on  its  outer 


Adductor  brevis 


Adductor  longua 


Adductor  magnus 


Vastus  InternuB 


Tendon  of  sartorius 


Gluteus  medius 


Glutens  minimus 
Tensor  vaginae  femoria 


Sartorius 


-  Rectus  femoris 


o-tibial  band  of  fascia  lata 


astua  ezternus 


Ligamentum  patellae 


Fir,.    2l8. — MUSCLES    OF    THE    FRONT    OF    THE    THIGH. 


•  border  is  the  vastus  cxternus.  (Fig.  2 1 8.)  Trace  the  rectus  upward  and  develop  its 
two  heads  (Fig.  226) :  (i)  The  straight,  from  the  anterior  inferior  iliac  spine  ;  (2)  the 
reflected,  from  the  depression  above  the  brim  of  the  acetabulum.  Notice  the  nerves 
and  arteries  enter  the  under  surface,  and  trace  them  to  their  sources.  (Fig.  223.) 


3i8  PRACTICAL    ANATOMY. 

The  Vasti  Internus  and  Externus  (Fig.  220). — Cut  the  rectus  four  inches 
above  the  patella  and  turn  it  aside,  guarding  well  the  vessels  and  nerves.  You 
will  take  particular  notice  of  the  form  of  the  groove  or  bed  in  which  the  rectus 
lay.  This  bed  is  on  the  front  surface  of  the  vastus  internus,  and  is  called  the 
crureus^  muscle.  (Fig.  220.)  It  is  not  a  separate  muscle,  but  only  that  part  of  the 
vastus  internus  on  which  the  rectus  lay.  Along  the  outer  margin  of  the  rectus-bed 
you  will  see  the  descending  branch  of  the  external  circumflex  artery  (Fig.  223), 


Femoral  vein 


Femoral  artery 

I 


Pectineus 
OBTURATOR  (ANTERIOR  DIV.) 

OBTURATOR  (POSTERIOR 
DIVISION) 


Adductor  longus 


Adductor  brevis 


OBTURATOR    — 
(ANTERIOR 
DIVISION) 


Oracilis 


Adductor  magnus 

GENICULA  TE 
BRANCH  OF 
OBTURATOR 

Seml-membranoBUB 


Anoitomotica  artery 


PA  TELLAR  BRANCH  OF 
LONG  SAPHENOUS 


Sartorlua 
Iliacus 

ANTERIOR  CRURAL 

Psoas 

Tensor  vaginae  femoris 

Prqfunda  artery 

Fectineus 
Hectus  femoris 

LONG  SAPHENOUS 


NERVE  TO  VASTUS 
IN  TERN  US 


Adductor  lonftus 


Femoral  artery 


FIG.  219. — ANTERIOR  CRIKAI    AND  <  IUTURATOR  NERVES.     (Ellis.) 

attended  by  the  nerve  to  the  vastus  externus.  This  artery  lies  in  a  groove  which 
separates  the  vastus  internus  from  the  vastus  externus.  Develop  this  groove, 
and  you  will  be  able  to  turn  the  vastus  externus  aside.  This  latter  muscle,  the 
vastus  externus,  overlaps  the  outer  part  of  the  vastus  interims  as  far  as  the  margin 
of  the  rectus.  (Fig.  218.)  Now  trace  the  rectus  and  the  two  vasti  downward  to 
their  conjoined  insertion  into  the  tubercle  of  the  tibia,  by  the  ligamentum  patelhe. 
(Fig.  216.)  Also  note  that  the  vastus  internus  receives  its  nerve-supply  on  ib 
anterior  surface.  (Fig.  219.) 

Obturator  Nerve  (Fig.  219). — This  is  a  branch  of  the  lumbar  plexus.    It  passe.- 


THIGH  AND   LEG. 


below  the  brim  of  the  pelvis,  with  the  obturator  artery  and  vein.  (Fig.  223.)  It 
escapes  from  the  pelvis  by  the  obturator  canal,  on  the  under  surface  of  the  hori- 
zontal ramus  of  the  pubes.  It  divides  into  anterior  and  posterior  branches.  These 
are  separated  by  the  adductor  brevis  muscle.  (Fig.  219.)  The  anterior  branch 


Obturator  externus 


Adductor  longus 


Adductor  magnus 


Adductor  longus 


Vastus  internus 


Reotua  femoris 


Xiigamentum  patellae 


Reotua  tendon 


GHuteus  medius 
Gluteus  minimus 


Adductor  brevis 


Vastus  ezternus 


Biceps 


Ilio-tibial  band 


FIG.  220. — THE  DEEP  MUSCLES  OF  THE^ FRONT  OF  THE  THIGH. 

supplies  the  graciiis,  adductor  longus,  adductor  brevis,  and  sartorius.     (Fig.  221.) 
The  posterior  branch  supplies  the  adductor  magnus,  the  knee,  and  the  hip. 

Branches  of  the  Anterior  Crural  Nerve. — This  nerve  is  from  the  lumbar 
plexus.  (Fig.  193.)  It  is  in  a  groove  under  the  crural  arch  between  the  iliacus 
and  psoas  magnus.  It  gives  off  the  following  branches  : 


320 


PRACTICAL   ANATOMY. 


1.  A  branch  to  the  iliacns  muscle.      This  is  given  off  within  the  pelvis,  but  is 
easily  found  distributed  to  the  under  surface  of  the  muscle. 

2.  Cutaneous    brandies — the     long    saphenous,    the    internal    and    middle 
cutaneous. 

3.  A  small  branch  to  the  femoral  artery.     This  is  given  off  within  the  pelvis. 

4.  Muscular  branches  to  all  the  muscles  on  the  front  of  the  thigh.      Note 
that  the  sartorius  muscle  is  supplied  either  by  the  middle  or  internal  cutaneous 
nerve. 

5.  An  articular  brancJi  to  the  hip,  given  off  from  the  branch  to  the   rectus  ; 
also  articular  branches  to  the  knee,  from  the  nerves  to  the  two  vasti. 


FIG.  221. — PECTIN EUS  AND  ADDUCTOR  LONGUS. 
I.   Femur.      2.  Ilium.      3.  Pubis.      4.   Pectineus. 

5.    Adductor    longus.       6.    Lower    portion    of 

adductor  magnus.     7.   Tendon  of  rectus  femoris. 

8,  8.  Orifices  for  vessels.     9.  Orifices  for  femoral 

vessels. 


FIG.  222. — ADDUCTOR  BRKVIS  AND  AI>DU 

MAGNUS. 

.  Femur.  2.  Ilium.  3.  Pubis.  4.  Obturator 
externus.  5-  Upper  portion  of  adductor  magnus. 
6.  Upper  portion  of  adductor  brevis.  7.  Inferior 
portion  of  adductor  brevis.  8.  Middle  portion 
of  adductor  magnu«.  9.  Inferior  portion.  lo. 
Tendon  of  insertion  into  internal  condyle  o 
femur.  n.  Orifice  for  femoral  vessels.  12. 
Orifice  for  internal  circumflex  artery  and  veins. 


Branches  of  the  Femoral  Artery. — The  common  femoral  is  a  continuation 
of  the  external  iliac.  (Fig.  223.)  Usually,  it  is  about  one  and  one-half  inches  in 
length.  It  then  divides  into  the  superficial  and  deep  femoral.  F.ach  has  branches. 

Branches  of  the  Common  Femoral  Artery. — (i)  Superficial  circumflex 
iliac  ;  (2)  superficial  epigastric  ;  (3)  superficial  external  pudic  ;  (4)  deep  external 
pudic.  These  are  all  small  and  surgically  insignificant  branches.  (Fig.  223.) 

Branches  of  the  Profunda. — (i)  The  internal  circumflex  ;  (2)  the  external 
circumflex  ;   (3)  the  three  perforating  arteries. 
arc  perforating  arteries  so  called .' 


1 1 


THIGH  AND   LEG.  321 

Because  they  perforate  the  adductor  group,  to  reach  the  hamstring  muscles 
on  the  back  of  the  thigh,  which  they  supply.  (Fig.  222.) 

The  external  circumflex  supplies  the  muscles  on  the  anterior  part  of  the 
thigh.  (Fig.  223.)  Its  ascending  branch  anastomoses  with  the  gluteal  and 
circumflex  iliac;  its  descending  branch  with  the  superior  external  articular  branch 
of  the  popliteal  artery. 

The  Use  of  the  Internal  Circumflex  (Fig.  223). — To  assist  the  obturator 
artery  in  supplying  the  hip-joint  and  the  adductor  muscles,  and  to  anastomose 
with  the  sciatic  and  external  circumflex  to  complete  the  crucial  anastomosis. 

\\rkcre,  on  the  posterior  part  of  tlic  thigh,  will  you  find  the  terminal  branch  of 
the  internal  circumflex  arterv  f 

Between  the  quadratus  femoris  and  the  adductor  magnus. 

Branches  of  the  Superficial  Femoral  Artery. — The  superficial  femoral 
artery  lies  in  both  Scarpa's  triangle  and  Hunter's  canal — surgical  areas  to  be  pres- 
ently described.  The  branches  given  off  by  this  artery  are  :  muscular,  to  the  sar- 
torius  and  vastus  interims  ;  the  anastomotica  magna,  given  off  just  before  the 
artery  leaves  Hunter's  canal. 

The  anastomotica  niagna  divides  into  two  branches:  (i)  A  superficial  one, 
that  accompanies  the  long  saphenous  nerve,  and  (2)  a  deep  one,  that  anastomoses 
with  the  internal  articular  and  the  anterior  recurrent  tibial.  This  artery  supplies 
branches  to  the  knee-joint.  It  will  be  found  on  the  bone,  above  the  condyle, 
forming  an  arch  with  the  external  articular. 

Review  of  tlic  Work  on  the  Thigh. — Thus  far  in  the  deep  dissection  of  the  an- 
terior and  lateral  regions  of  the  thigh,  you  have  : 

1.  Traced  the  origin,  insertion,  and  nerve-supply  of  the  sartorius,  and  lifted 
this  muscle  from  its  bed. 

2.  You  have  found  the  exact  origin  and  insertion  of  the  gracilis,  and  liberated 
the  same  without  doing  violence  to  its  nerves  and  blood-vessels. 

3.  You  have  traced  the  adductor  longus  from  origin  to  insertion,  preserved 
its   nerves,  cut  the   origin  of  the  muscle,  and  seen  the  anterior  division  of  the 
obturator  nerve  lying  below,  on  the  adductor  brevis  muscle  ;  and  the  branches  of 
this  nerve  you  have  followed  to  four  muscles. 

4.  You  have  located  the  anterior  crural  nerve  in  a  space  between  the  psoas 
magnus  and  iliacus,  taken  this  nerve  up,  and  traced  out  its  branches  to  the  muscles 
on  the  front  part  of  the  thigh  and  to  the  skin  covering  these  muscles  and  to  the 
joints  these  muscles  move. 

5.  You  have  removed  the  rectus  from  its  bed,  traced  the  same  to  its  origins, 
and  preserved  the  nerve-  and  blood-supply  ;  finally,  you  have  cut  the  rectus  four 
inches  above  the  patella. 

6.  You  have  seen  that  the  crureus  is  not  a  separate  muscle,  but  a  part  of  the 
vastus  intern  us. 

7.  You   have  traced  the  femoral  artery  well  down  and  studied  its  profunda 
division. 

8.  You  have  traced  the  vasti  and  rectus  to  their  common  insertion  into  the 
tubercle  of  the  tibia  by  the  ligamentum  patella:,. 

What  to  Dissect  Next. — (i)  Cut  the  origin  of  the  adductor  brevis  (Fig.  220), 
gently  lift  the  same,  and  see  the  posterior  division  of  the  obturator  nerve.  Trace 
this  nerve  to  the  adductor  magnus  and  obturator  externns  muscles.  (2)  Cut  the 
pectineus  (Fig.  219)  and  turn  it  down.  Now,  on  the  outer  surface  of  the  obturator 
externns  muscle  you  will  find  the  o bturator  artery,  anastomosing  with  the  internal 
circumflex,  a  branch  of  the  profunda.  (Fig.  223.)  (3)  Now  you  may  replace 
in  this  order  the  muscles  you  have  cut  and  turned  aside  :  (a)  Pectineus,  (^) 
adductor  brevis,  (r)  adductor  longus,  (d)  rectus.  Place  the  sartorius  in  its 
original  oblique  position. 


322 


PRACTICAL   ANATOMY. 


Two  Important  Surgical  Areas. — Scarpas  triangle  and  Hunter  s  canal. 

Scarpa's  triangle  is  located  on  the  upper  anterior  one-third  of  the  thigh.  It 
is  divided  into  an  inner  and  an  outer  part  by  the  femoral  vessels,  which  bisect  the 
space  vertically.  It  is  of  surgical  importance  for  the  following  reasons  : 

1.  Inguinal  and  femoral  herniae  are  seen  here. 

2.  Varicocele,  dilatation  of  scrotal  or  spermatic  veins. 

3.  Removal  of  inguinal  lymphatic  glands  may  become  necessary. 

4.  Fracture  of  the  femur  and  dislocations  of  its  head. 


Common  iliac  artery 
SYMPA  THETIC  NER  VE 

Middle  sacral  artery 


Common  iliac  vein 
URETER 

Internal  iliac  artery 

External  iliac  vein 

External  iliac  artery 

Potterior  branch  of  internal  iliac  dividing  into 
gluteal  and  ilio-lumbar  arteries 

Lateral  sacral  artery 

SACRAL  PLEXUS 

OBTURATOR  NERVE 
Obturator  artery 
Obliterated  hypngastric 

Superior  vetical  artery 
Edge  of  levator  ani 

Pudic  artery 

BLADDER 

Middle  vesical  artery 

Deep  epigastric  artery 
Pubic  branch  of  epi- 
gastric artery 
Common  femoral  artery 

Long  saphenons  vein 
Pectineus  muscle 

Obturator  artery 

Adductor  magnus 

Internal  circumflex  artery 

Adductor  brevis 

OBTURATOR  NERVE  (ant.  branch) 

Profunda  artery 

Adductor  longus,  hooked  aside 

Superficial  femoral  artery  and  vein  . 


Oracilis  muscle 
Lower  part  of  sartorius 


Psoas  muscle 
Ilio-lumbar  artery 

EXTERNAL  CUTA- 
NEOUS NERVE 

Iliacus  muscle 

GE. \ITO-CRURAL 
NER  VE 

ANTERIOR  CRU- 
RAL NERVE 


Deep  circumflex  iliac 

artery 
Superficial  circumflex 

iliac  artery 

A.VTERIOR  CRfRAL  AT. 
Gluteal  artery  and 

Tensor  fasciae  femoris 

(hooked  aside) 
Glutens  mediuB  and 

minimus 
Sartorius  muscle 
MIDDLE  CUTA- 
NEOUS NERVE 

NER  VE  TO  RECTUS 

A'ERVE  TO  VASTl-S 
BXTKRXl'S 

External  circumflex  ar. 
XERVB  TO  CRl'REUS 
Rectus,  hooked  aside 

/.  o.\(";  SAPBBNO I 'S 
NERVE  A\I) 
NERVE  TO  IMN- 
TUS  INTERNUS 


Vastus  internus 
muscle 


FIG.  223.— TUP,  FKMORAI.  ARTKRY  IN  SCAKTA'S  TKIANCI.I. 
(From  a  dissection  by  W.  J.  Wai  sham  in  St.  Bartholomew's  Hospital  Museum.) 

5.  Burrowing  of  pus  from  regions  above  may  point  here. 

6.  Bloodless  amputation  at  the  hip  involves  this  region. 

7.  Injuries  to  the  vessels  and  nerves  in  the  space  may  occur. 

The  triangle-  should  be  studied  as  having  tin-  following  geometrical  parts  :  (I 
Roof:  skin,  superficial  and  deep  fascia.-.  (2)  Floor:  iliacus,  psoas,  pectineus,  and 
adductor  longus.  (3)  Superior  boundary  :  Poupart's  ligament.  (4)  Internal 
boundary  :  adductor  longus  muscle.  (5)  Fxternal  boundary  :  the  sartorius  muscle. 
(6)  The  base:  the  superior  boundary.  (7)  The  apex  :  conjunction  of  adductor 


THIGH  AND   LEG. 


3Z3 


longus  and  sartorius.  Contents :  (a)  The  femoral  sheath,  formed  of  the  iliac  fascia 
behind  the  vessels,  and  the  transversalis  fascia  in  front  of  the  same.  This  sheath 
contains  the  femoral  artery,  vein,  and  femoral  canal.  (Fig.  212.)  (b)  The  termina- 
tion of  the  longsapJienous  vein,  (c}  The  external  cutaneous  nerve  of  the  thigh,  which 
you  will  find  under  the  anterior  superior  iliac  spine.  (//)  The  spermatic  cord  in 
the  male,  and  its  homologue,  the  round  ligament,  in  the  female,  both  of  which 
you  will  find  under  the  spine  of  the  pubes.  (Fig.  224.)  (e)  The  obturator  nerve 
and  vessels.  (/)  The  lesser  trocJianter  of  the  femur,  giving  insertion  to  the  iliacus 
and  psoas  magnus  muscles  ;  (^)  the  anterior  crural  or  femoral  nerve  and  its 
branches  ;  (/^)  the  common  femoral  artery  and  vein,  bifurcating  into  the  profunda 
and  superficial  femoral  arteries.  In  this,  as  in  other  regions,  the  student  should 
become  so  familiar  with  structures  that  he  can,  by  the  sense  of  feel  alone,  say 
positively  what  he  touches.  I  remember  well  a  freshman  examined  the  deep 


Obliquus 

interims 

Aponeurosis 
of  obliquuB 

externus 

Spermatic 

cord 

Origin  of 
cremaster 
Triangular 
fascia 

Insertion  of 
cremaster 


Loops  of 
cremaster 


Intercolumnar 
fibres 


FIG.  224. — OULIQUUS  EXTERNUS  AND  FASCIA  LATA. 


part  of  Scarpa's  triangle,  and  feeling  the  lesser  trocJianter  of  the  femur,  made  a 
diagnosis  of  osteo-sarcoma  ! 

Poupart 's  ligament,  or  crural  arch,  is  the  lower  part  of  the  aponeurosis  of  the  ex- 
ternal oblique  muscle  of  the  abdominal  wall.  (Fig.  224.)  It  extends  from  the 
anterior  superior  iliac  spine  to  the  pubic  spine.  It  is  continuous  below  with  the 
fascia  lata.  (Fig.  212.)  It  forms  the  floor  of  the  inguinal  canal,  upon  which 
floor  rest  the  spermatic  cord  and  round  ligament  of  the  uterus,  just  before  they 
emerge  through  the  external  abdominal  ring  into  Scarpa's  triangle. 

Hunter  s  canal  (Fig.  219)  (i)  extends  from  the  apex  of  Scarpa's  triangle  to 
the  aperture  in  the  adductor  magnus  muscle.  (Fig.  222.)  In  other  words,  it  is  a 
groove  linking  together  the  popliteal  space  and  Scarpa's  triangle.  (2)  It  is 
bounded  externally  by  the  inner  part  of  the  vastus  internus  muscle  ;  internally  by 
the  front  surfaces  of  the  adductor  longus  and  adductor  magnus  muscles.  (3)  Its 
roof  is  the  deep  fascia  passing  across  from  the  adductors  to  the  vastus  internus. 

It  contains  :  (i)  The  superficial  femoral  artery  and  vein.      The  vein  lies  behind 


324 


PRACTICAL  ANATOMY. 


the  artery,  according  to  the  rule  governing  the  relations  of  veins  and  arteries 
below  the  diaphragm.  (2)  The  long  saphenous  nerve.  Note  that  this  nerve  is  on 
the  outer  side  of  the  artery.  (3)  The  communicating  branch  to  the  obturator 
nerve  via  the  subsartorial  plexus. 

Explain  the  quadriceps  femoris. 

This  is  a  collective  noun  indicating  a  four-headed  muscle,  on  which  depends 


LEVEILLE  0£i  f.'t* 

FIG.  225. — MU.-.CLE;  OF  THE  ANTERIOR  ASTECT  <>K   TIIK  I'.ODY. 
\.   Pectoralis  major.     2.   Its  clavicular   fasciculus.     3.   Fasciculus  attached    to    abdominal    aponeurosi 
4,4.  External  oblique.     5,5.    Serratus  magnus.     6,6.   Anterior  border  of  latissimus  dorsi.      7.   De 
cassation  of  tendinous    fibers    of    pectorales   majores.     8.    Ensiform    cartilage.      9,    9.     Abdominal 
aponeurosis.     IO,   IO.   Linea  alba.      II.    Umbilicus.      12,    12,    12.   Tendinous  intersections  of  rectus 
abdominis.     13,13.   External  abdominal  ring.      14.   Pyramidalis.      15,15.    External  border  of  rect 
abdominis.       16.    Sterno-hyoid.     17.   Omo-hyoid.      18.    Sterno-mastoid.      19.    Cervical    portion 
trapezius.     20.     Deltoid.       21.     Biceps    brachialis.     22.     Pectineus.     23.     Sartorius.       24.     Kectus 
femoris.      25.   Tensor  vaginre  femoris. 

extension  of  the  leg.  The  individual  muscles  forming  the  extensor  quadriceps 
femoris  all  converge  to  form  one  tendon, — the  ligamentum  patellae, — which  is 
inserted  into  the  tubercle  of  the  tibia.  (Fig.  220.)  These  muscles,  from  their 
diverse  origin  and  extensive  attachments  t<»  the-  femur  and  ilium,  represent  both 
strength  and  celerity  of  motion — not  an  easy  combination.  The  rectus,  vastus 


THIGH  AND   LEG. 


325 


externus,  vastus  interims,  and  crureus  make  up  the  extensor  musculature.  Trace 
these  muscles  to  the  following  origins  (from  Morris)  : 

The  Rectus. — Origin. — Anterior  head,  from  the  front  of  the  anterior  inferior 
spine  of  the  ilium  ;  posterior  head,  from  the  upper  surface  of  the  rim  of  the 
acetabulum  just  external  to  the  attachment  of  the  capsular  ligament. 

Vastus  Externus. — Origin. — (i)  The  upper  half  of  the  anterior  intertro- 


Posterior  limit  of  external  oblique 


Insertion  of 
external  oblique 


Internal  oblique 


Tensor  vaginas 
t'emoris 


Rectus  femoris 


ARTICULAR  PORTION  OF 
COTYLOID  CAVITY 


PECTINEAL  RIDGE 


Fectineus 

Rectus 
abdominis 
Pyramidalis 
Adductor 

longus 

Adductor 

brevis 


DESCENDING  RAMUS 
OF  PUBES 

Graoilis 


Latissirnus  dorsi 


CREST  OF  ILIUM 


SUPERIOR  GLUTEAL 
RIDGE 


OBTURATOR  NOTCH 
Semimembranosus 


Quadratus  femoris 


Semitendinosus 
and  bicepa 


_  Adductor  magnus 


RAMUS  OF  ISCHIUM       Obturator  externus 

FIG.  226. — THE  LEFT  HIP-BONE.     (Posterior  view.) 
(Trace  out  the  origin  and  insertion  of  muscles  and  consult  this  figure.) 

chanteric  line  and  the  front  of  the  upper  part  of  the  femur  along  the  anterior  border 
of  the  great  trochanter  ;  (2)  a  horizontal  line,  which  forms  the  lower  border  of  the 
great  trochanter  ;  (3)  the  outer  lip  of  the  gluteal  ridge  ;  (4)  the  upper  half  of 
the  outer  lip  of  the  linea  aspera  and  the  adjacent  portion  of  the  shaft  of  the  femur 
for  about  one-sixth  of  an  inch  ;  (5)  the  external  intermuscular  septum  in  the 
neighbourhood  of  its  attachment  to  the  linea  aspera. 

Vastus  Interims. — Origin. — (i)  The  outer  lip  of  the  lower  half  of  the  linea 


Obturator  extcrnus 


Gluteus  rnediue 


TUBERCLE  OF  THE 
quadratus  femoris 


Ligamentum  teres 


Capsule 

POSTERIOR  INTERTROCHANTERIC  LINE 

Faoas 

LESSER  TROCHANTER 

Iliacus 
Peotineus 


Adductor  brevis 


INTERVENING  SPACE  OF  THE  LINEA  ASPERA. 
Adductor  longus 


Vastus  internuB 

INNER  LIP  OF  THE  LINEA  ASPERA 


NUTRIENT  FORAMINA 


FOR  FEMORAL  ARTERY 


INTERNAL  CONDYLAR  LINE 
Adductor  magnus 


Flantaria 
Oaatrocnemius 


Anterior  crucial  ligament 
INTERCONDYLOID  NOTCH 


ADDUCTOR  TUBERCLE 
Gaatrocnemius 


lateral  ligament 


EXTERNAL  CONOYLE 


INTERNAL  CONDYLE 


Posterior  crucial  ligament 

FIG.    227. — Tin     I  ill     IIMIK.      (Posterior  view.) 

(Study  the  insertion  of  the  adductor  on  this  figure.) 

326 


GREATER  TROCHANTER 


SUPERIOR  CERVICAL  TUBERCLE 


Capsule 

OF  THE  HIP-JOINT  ATTACHED  TO  THE  ANTERIOR 
INTERTROCHANTERIC  LINE 


LESSER  TROCHANTER 
Fsoas 


Pyriformis 
Obturator  internua 


ADDUCTOR  TUBERCLE 
Adductor  magnus 


External  lateral  ligament 
Fopliteua 


INTERNAL  CONDYLE  EXTERNAL  CONDYLE 

FIG.  228. — THE  LEFT  F£MUR.     (Anterior  view. 
(Study  the  origin  of  the  vasti  on  this  figure.) 


328  PRACTICAL   ANATOMY. 

aspera  and  its  external  bifurcation,  together  with  the  adjacent  external  inter- 
muscular  septum  ;  (2)  the  lower  part  of  the  anterior  intertrochanteric  line  and  the 
spiral  line  of  the  femur;  (3)  the  inner  lip  of  the  whole  length  of  the  linea  aspera 
and  its  internal  bifurcation,  together  with  the  adjacent  part  of  the  internal  inter- 
muscular  septum,  and  the  front  of  the  tendon  of  the  adductor  magnus  ;  (4)  the 
greater  part  of  the  front  and  sides  of  the  femur  within  the  limits  formed  by  the 
three  preceding  attachments  and  the  origin  of  the  vastus  externus. 

The  Physiological  Adductors  of  the  Thigh. — In  figure  222  this  group  of 
muscles  may  be  seen.  They  are  four  in  number.  They  are  supplied  by  the 
obturator  nerve.  They  are  all  ligamentous  in  action  to  the  hip-joint  ;  hence  the 
obturator  nerve  will  send  a  nerve  to  this  joint.  They  all  figure  conspicuously  in 
the  architecture  of  Scarpa's  triangle  and  Hunter's  canal.  Study  the  origin  ot 
these  muscles  very  carefully  on  figure  226,  and  then  on  the  cadaver,  as  follows  : 

The  adductor  longus  arises  from  the  anterior  surface  of  the  body  of  the  pubis 
immediately  below  the  crest  and  angle. 

The  adductor  brevis  arises  from  the  bo'dy  and  ramus  of  the  pubis,  below  and 
external  to  the  origin  of  the  adductor  longus.  If  the  student  will  study  the 
divergence  of  the  ischio-pubic  rami,  he  will  then  understand  why  the  origin  of 
the  adductor  brevis  is  described  as  external  to  that  of  the  adductor  longus. 

The  adductor  magnus  arises  from  the  tuber  of  the  ischium,  and  from  the 
ischio-pubic  ramus.  (Fig.  226.)  Examine  the  perforations  in  this  muscle  for 
the  superficial  femoral  artery  to  pass  into  the  popliteal  space. 

Name  the  adductor  muscles  and  give  their  insertions.     (Fig.  227.) 

Adductor  longus,  inserted  into  middle  lip  of  linea  aspera,  middle  one-third. 

Adductor  brevis,  inserted  into  middle  lip  of  linea  aspera,  upper  one-third. 

Adductor  gracilis, inserted  into  inner  surface  of  tibia,  upper  one-third.  (Fig.  216.) 

Adductor  magnus,  inserted  :  (i)  Into  the  back  of  the  femur,  in  a  line  beginning 
at  the  lower  extremity  of  the  linea  quadrati,  and  extending  along  the  inner  border 
of  the  gluteal  ridge  and  the  middle  of  the  linea  aspera  down  to  its  bifurcation  ; 

f        t  • 

(2)  into  the  adductor  tubercle  on  the  upper  and  posterior  part  of  the  internal 
condyle  ;  (3)  into  the  lower  part  of  the  internal  intermuscular  septum. 

Fascial  Septa. — Having  thoroughly  dissected  all  the  muscles  on  the  inner 
part  of  the  thigh  and  front  part  of  both  leg  and  thigh,  I  now  desire  you  to  answci 
these  questions  : 

1.  How  many  musculatures   have  you  found — that  is,  lioiv  many  groups 
muscles  acting  in  unison  f 

You  say  :  (i)  An  extensor  group,  innervated  by  an  extensor  nerve,  called  an- 
terior crural  or  femoral  ;  (2)  a  flexor  group,  on  the  posterior  part  of  the  thigh, 
innervated  by  a  flexor  nerve,  called  the  great  sciatic  ;  (3)  an  adductor  group,  on  the' 
inner  part  of  the  thigh,  innervated  by  an  adductor  nerve,  called  the  obturator  ; 
(4)  an  abductor  group,  on  the  outer  side  of  the  pelvis,  innervated  by  the  superior 
gluteal,  an  abductor  nerve  ;  (5)  *  group  OH  t lie  front  of  the  leg — flexors  of  the  tarsus 
and  extensors  of  the  toes — supplied  by  the  anterior  tibial  nerve  ;  (6)  a  group  on  the 
outer  surface  of  the  fibula,  supplied  by  the  muscular  branches  of  the  musculo-cuta- 
neous  nerve  ;  (7)  two  groups  of  muscles  on  the  posterior  part  of  the  /eg,  innervated 
by  the  internal  popliteal  nerve,  extensors  of  the  tarsus  and  flexors  of  the  toes. 

2.  Are  the  groups  individually  separated  from  eaeli  other  by  septa  f 

You  answer  yes,  for  you  have  found  a  fascial  septum  between  the  adductors 
and  extensors  ;  between  the  flexors  and  adductors  ;  between  the  anterior  and 
lateral  groups  below  the  knee  ;  between  the  lateral  and  posterior  groups  ;  be- 
tween the  superficial  and  deep  groups  on  the  back  of  the  leg. 

3.  Arc  these  intermuscular  septa  attached  to  bone  f    Do  they  in  any  manner 
origin  to  muscle  .'     Are  they  derived  from  deep  fascia  f 

You  answer  the  above  in  the  affirmative, 


,  THIGH  AND    LEG.  329 

Anatomical  transition  is  never  abrupt,  but  gradual.  Compact  bone-tissue 
gradually  merges  into  cancellous ;  muscle  gradually  becomes  tendinous ;  at 
muco-cutaneous  areas  skin  and  mucous  membrane  gradually  partake  of  the 
nature  of  each  other.  The  transition  from  extension  of  the  leg  to  adduction  of 
the  thigh  would  be  abrupt.  This  is  moderated  by  the  sartorius  muscle,  which, 
in  consequence  of  its  dual  function,  has  a  double  nerve-supply  and  an  indepen- 
dent fascial  sheath.  The  adductor  magnus  moderates  between  flexion  and 
adduction  ;  hence  its  dual  nerve-supply. 

The  Femur  (Figs.  227  and  228). — Name  the  points  of  the  femur  of  impor- 
tance in  practical  anatomy. 

The  head  articulates  with  the  acetabulum. 

The  neck  joins  the  head  of  the  bone  to  the  shaft. 

The  greater  trochanter  facilitates  axial  rotation. 

The  lesser  trochanter  facilitates  axial  rotation. 

The  tereal  depression  is  for  the  ligamentum  teres. 

The  digital  or  trochanteric  fossa  is  for  the  obturator  externus. 

The  intertrochanteric  lines  are  anterior  and  posterior. 

The  oblique  line  of  the  greater  trochanter  is  for  the  gluteus  medius. 

The  anterior  intertrochanteric  line  is  for  the  capsule. 

The  tip  of  the  greater  trochanter  is  for  the  gemelli,  pyriformis,  obturator  ex- 
ternus. 

The  condyles  articulate  with  the  tibia  and  patella. 

The  condylar  ridges  limit  laterally  the  popliteal  surface. 

The  intercondylar  notch  lodges  the  crucial  ligaments. 

The  patellar  facet  articulates  with  the  patella. 

The   adductor  tubercle  is  for  the  adductor  magnus  tendon. 

How  and  ivJicrc  are  (lie  glntcal  muscles  inserted  / 

They  are  inserted  principally  by  tendon  as  follows  :  The  gluteus  maximus 
into  the  gluteal  ridge  ;  the  gluteus  medius  into  the  oblique  line  of  the  greater 
trochanter  ;  the  gluteus  minimus  in  the  anterior  border  of  the  greater  tro- 
chanter. 

What  is  the  third  trochanter  / 

A  name  given  to  the  gluteal  ridge  when  this  is  unusually  prominent.  Growth 
is  the  correlative  of  function  ;  where  extraordinary  function  is  imposed  on  any 
group  of  muscles,  or  on  any  single  muscle  of  a  group,  the  bony  insertion  point 
of  the  muscle  will  be  correspondingly  increased  in  size.  Trochanter  means  a 
bony  eminence  for  muscular  attachment,  situated  favorably  for  axial  rotation  of 
the  limb  ;  hence  the  name,  third  trochanter. 

Describe  the  line  a  asp  era. 

This  may  be  compared  to  a  tree  with  (i)  a  trunk,  (2)  definite  roots,  (3)  definite 
branches  above.  Now,  when  we  speak  in  general  terms  of  a  tree,  we  have  in 
mind  the  trunk  ;  when  we  speak  specifically  of  this  object  as  a  shade-tree,  we  have 
in  mind  the  branches  ;  when  we  speak  specifically  of  its  attachments  to  the  earth, 
we  have  in  mind  the  roots  of  the  tree.  The  linea  aspera  has  a  trunk  which  is  in 
the  middle  one-third  of  the  femur  ;  branches  which  ramify  definitely  in  the  upper 
one-third  of  the  femur;  roots  which  are  definitely  disposed  in  the  lower  one- 
third  of  the  femur. 

Describe  the  trunk  of  the  linea  aspera. 

It  is  composed  of  three  lips  or  ridges,  produced  by  muscular  traction  ;  these 
lips  are  called  outer,  middle,  inner.  This  part  of  the  linea  aspera  occupies  the 
middle  one-third  of  the  shaft  of  the  femur,  and  forms  the  posterior  border  of  the 
same. 

How  is  the  root  of  the  linea  aspera  disposed  f 

The   outer   lip   is   continued  downward   and  outward  to  the  condyle  of  the 


330  PRACTICAL  ANATOMY.  , 

femur  as  the  external  condylar  ridge.  The  inner  lip  is  continued  downward  to 
the  adductor  tubercle  as  the  internal  condylar  ridge.  The  middle  lip  is  continued 
downward,  and  expands  to  form  the  popliteal  surface  of  the  femur. 

Hou  arc  the  branches  of  the  linen  aspera  disposed  / 

The  inner  lip  continues  upward,  around  and  below  the  lesser  trochanter,  as 
the  spiral  line  ;  to  the  lower  half  of  this  spiral  line  is  attached  the  vastus  externus  ; 
to  the  upper,  the  capsule  of  the  hip-joint. 

The  outer  lip  of  the  linea  aspera  continues  upward  and  outward,  and  ends  at 
the  base  of  the  great  trochanter  in  the  gluteal  ridge  for  the  gluteus  maximus. 

The  middle  lip  divides  into  an  inner  and  an  outer  division.  The  inner  breaks 
up  into  two  branches, — one  for  the  iliacus,  the  other  for  the  pectineus  muscle, — both 
of  which  continge  the  lesser  trochanter.  The  outer  division  of  the  middle  lip 
of  the  linea  aspera  terminates  above  as  a  vertical  ridge,  midway  between  the 
trochanters,  as  the  linea  quadrati,  for  the  insertion  of  the  quadratus  femoris. 

Describe  the  attachment  of  muscles  to  the  three  lips  of  the  trunk  of  the  linea 
aspera. 

To  the  outer,  the  short  head  of  the  biceps  femoris  and  the  vastus  externus  ; 
to  the  inner  lip,  the  vastus  internus  ;  to  the  middle  lip,  the  adductor  brevis,  adduc- 
tor longus,  and  adductor  magnus. 


THE  PELVIC  OUTLET. 

Locate  :  (i)  The  subpubic  arch  ;  (2)  the  tuberosities  of  the  ischium  ;  (3)  the 
tip  of  the  coccyx  ;  (4)  the  ischio-pubic  ramus  on  each  side,  and  give  its  com- 
position ;  (5)  the  spine  of  the  pubes  ;  (6)  the  symphysis  pubis. 

'  Place  the  subject  in  the  position  shown  in  figure  229 — /.  e.}  flex  the  leg  on 
the  thigh,  the  thigh  on  the  abdomen,  and  abduct  the  thighs.  Now  fill  the  rectum 
with  cotton  and  sew  the  margins  of  the  anus  together.  Do  not  take  your  stitches 
too  deeply — one-fourth  of  an  inch  external  to  the  junction  of  the  skin  and 
mucous  membrane  is  enough. 

Incisions. — (i)  Cut  from  the  subpubic  arch  through  the  skin  to  the  front 
margin  of  the  anus  ;  then  from  the  posterior  margin  of  the  anus  to  the  tip  of 
the  coccyx  ;  (2)  cut  from  one  tuberosity  of  the  ischium  to  the  other  ;  (3)  make 
a  circular  incision  around  the  anus  just  a  little  outside  of  the  stitches  employed 
in  sewing  together  the  margins  of  the  anus  ;  (4)  now  begin,  and  dissect  back  the 
four  flaps.  The  greatest  care  must  be  taken  to  keep  the  skin  very  thin — thin 
enough  to  see  through. 

You  have  now  removed  the  skin  from  the  outlet  of  the  pelvis.  This  space 
is  diamond  in  shape,  and  has  the  following  boundaries  :  Two  lines  above  and  two 
below  will  outline  the  space  called  the  pelvic  outlet — (i)  a  line  from  the  tuberos- 
ity of  the  ischium  to  the  subpubic  arch  on  each  side  above  ;  (2)  a  line  from  the 
tip  of  the  coccyx  to  the  tuberosity  on  each  side  below.  This  outlines  two 
triangles  with  their  bases  together  on  an  imaginary  line  from  one  tuberosity  to 
the  other. 

The  anterior  triangle  is  called  the  permeal ;  the  posterior,  the  ischio- 
rectal.  Continue  removing  skin  until  yon  have  exposed  a  space  as  lar^e  as  that 
represented  in  figure  229.  The  next  step  is  to  introduce  a  sound  into  the 
bladder,  and  retain  it  there  by  means  of  string  tied  tightly  around  the  penis  near 
the  end. 

A  dissection  of  this  region   really  consists  of  only   two  stages:  (i)  Of  the 


THIGH  AND   LEG. 


331 


structures  seen  in  figures  229  and  230;  (2)  of  structures  seen  in  figure  233. 
After  having  removed  the  skin,  only  a  little  developing  is  necessary  to  expose 
all  the  structures  seen  in  figures  229  and  230.  To  give  an  adequate  idea  of  the 
subject,  study  the  following  to  learn  what  you  are  expected  to  find  in  the  first 
stage  of  the  dissection  : 

1.  The  deep  layer  of  the  superficial  fascia  that  you  see  in  figure  230  turned 
outward  and  marked  Colics'  fascia.      Notice  this  is  attached  to  the  ischio-pubic 
ram  us  and  to  the  triangular  ligament,  whose  cut  edge  shows  in  figure  230.    This 
is  called  the  fascia  of  Colles. 

2.  Around  the  anus  you  will  see  a  very  delicate  layer  of  muscular  fibres  that 

BUL80-CAVERNOSUS 

Superficial  triangular  ligament 
ISCHIO-CAVERN03U8 


INFERIOR  PUDENDAL  NERVE 

.-ri'j-i:i-ir/AL  I'KI;I.\\EAL  NERVE 

INFERIOR  llJEMOHIilfOIUAL  NERVE 
CUTANEOUS  BRANCH  OF  FOURTH  SACRAL 


Gluteus  maximus 

TUBEROSiTY  OF  ISCHIUM 
Great  sacro-sciatic  ligament 
Levator  ani 
Superficial  transveraua  perinaei 


Sphincter  aui 
FIG.  229. — THE  MALE  PERINEUM.     (Modified  from  Hirschfeld  and  LeveillS.) 


throws  the  margin   of  the  anus  into  folds — the  corrugator  cntis  ani,  a  dermal 
muscle. 

3.  In  the  anterior  triangle  you  see  the  three  large  pyramids  originating,  \\hich 
come  together  to  form  the  penis:   (i)  The  bulb  in  the  centre,  being  the  lower 
part  of  the  corpus  spongiosum  ;   (2)  the  crura,  parts  of  the  corpora  cavernosa 
on  each  side,  in  firm  connection  with  the  ischio-pnbic  rand. 

4.  The  bulb,  covered  by  a  muscle  called  the  accelerator  nriwc  in  the  male. 
Depress  the   sound  and  you  can  make  this  bulb  stand  out  very  prominently. 
(Fig.  230.) 

5.  Tlie  cms  penis,  covered  by  a  muscle  called  the  erector  penis — ischio-cavern- 


332 


PRACTICAL  ANATOMY. 


osus — in  the  male.     Pull  the  penis  upward  and  from  side  to  side  gently,  and  this 
will  bring  the  crura  and  their  investing  muscles  into  view.      (Fig.  239.) 

6.  The  external  spliineter  aid  you  will  see  reaching  from  the  tip  and   sides  of 
the  coccyx,   surrounding   the   anus,   to   the   central  perineal  point.      The  outer 
margins  of  this  muscle  seem  to  become  lost  in  a  quantity  of  fatty  and  connective 
tissue. 

7.  Another    muscle,    the   superficial   transversns  perilled,    lies    between    the 
sphincter  ani  and  the  erector  penis,  extending  in  an  oblique  direction  from  the 
tuberosity  of  the  ischium  to  the  central  perineal  point. 

8.  Tlie  central  perineal  point,  or  tendinous  centre  of  the  perineum,  is  in  the 
mid-line  from  side  to  side  and  about  one  inch  in  front  of  the  anus.     As  you  will 


Superficial  perinceal  vessels 


Accelerator  urinae 


Colles'B  fascia,  turned  back 


Erector  penis 

Transverse  perinceal  vessels 
Cut  edge  of  triangular 

ligament 

SUPERFICIAL  PERIXJEAL 
NERVE  GIVING  OFF 
TRA  NS  VERSE  BRA  NCH 
Pudic  vessels 

Inferior  hamarrhoidal  vessels 
and  nerves 


Glutens  maximus 
hooked  back 


Dorsal  artery  of  penis 
Artery  of  crus 


Great  sciatic  ligament 
Levator  ani 
External  sphincter 


FIG.  230. — THE  ARTERIES  OF  THE  PERINEUM. 
On  the  right  side  Colics'  fascia  has  been  turned  back  to  show  the  superficial  vessels.     On  the  left  side  the 
superficial  vessels  have  been  cut  away  with  the  anterior  layer  of  the  triangular  ligament  to  show  tin- 
deep  vessels. 


demonstrate  in  your  dissection,  and  as  you  may  see  in  figure  229,  this  point  is 
where  the  following  muscles  meet:  (i)  The  sphincter  ani  ;  (2)  the  superficial 
transversus  perinaei  ;  (3)  the  accelerator  urinae  or  bulbo-cavernosus. 

9.  The  levator  ani  shows  well  in  both  figures,  but  at  this  stage  of  the  dissec- 
tion is  obscured  by  (i)  the  sphincter  ani  and  (2)  the  large  mass  of  fat  in  the 
ischio-rectal  fossa.     The  muscle  is  seen  in  figure  230  on  each  side  of  the  anus. 

10.  The  space  on  each  side  of  the  anus   is  the  ischio-rectal  fossa.      It  is  now 
full    of  fat.      Figure   230  shows  this  fat   removed    and   the  levator  ani   muscle 
divested  of  the  anal  fascia. 

1 1.  The  greater  saero-seiatie  ligament  must  now  be  located.      In  the  figures  it 
is  shown  cut  on  one  side  to  expose  the  internal  pudic  structures. 

12.  Notice  the  luzmorrhoidal branches t  ami  the  perineal  branches  of  the  internal 


THIGH  AND   LEG. 


333 


pudic  vessels  and  nerves  ;  also  the  inferior  pudendal  nerve,  a  branch  of  the  small 
sciatic,  distributed  to  the  scrotum  and  side  of  the  thigh. 

Dissection. — Locate  the  greater  sacro- sciatic  ligament.  Cut  this  ligament  and 
find  under  the  same,  in  the  lesser  sacro-sciatic  foramen,  the  main  branches  of  the 
internal  pudic  nerve  and  vessels.  You  will  find  two  fair-sized  branches  given  off. 
Tuey  will  both  be  found  to  break  up  into  numerous  branches.  Now  carefully 
trace  these  branches  through  the  fat  of  the  iscldo-rectal  fossa — the  one  to  the 
anus,  the  other  forward  to  the  perineum.  The  branch  to  the  anus  is  the  inferior 
li&morrhoidal ;  the  other  is  the  superficial perineal.  Notice:  (i)  These  branches 
are  both  from  the  internal  pudic  ;  (2)  each  divides  into  cutaneous  and  muscular 
branches,  for  the  supply  of  the  muscles  and  the  skin  in  these  regions.  The 
arteries  follow  the  nerves  and  take  the  same  name.  The  internal  pudic  nerve 
now  continues  in  a  canal — called  Alcock's.  This  nerve  pierces  the  posterior 
layer  of  the  triangular  ligament  (Fig.  233),  and  gives  off  the  following  branches  : 
(i)  The  dorsal  nerve  of  tlie penis ;  (2)  nerve  to  the  bulb ;  (3)  nerve  to  the  corpus 
cavernosum  ;  (4)  superficial  perineal.  This,  the  dorsal  nerve  of  the  penis,  is  the 
largest  division  of  the  internal  pudic  nerve.  You  will  find  it  on  the  inner  sur- 
face of  the  ramus  of  the  ischium.  It  passes  behind  the  superficial  transversus 


Superficial  dorsal  vein  of  penis 

/Deep  dorsal  vein 
Dorsal  artery 


TUNICA  ALBUGINEA 


Vessels 


TUNICA  ALBUGINEA 


Artery 


Artery 
URETHRA 
CORPUS  SPONGIOSUM 


FIG.  231. — TRANSVERSE  SECTION  THROUGH  THE  BODY  OK  THE  PENIS. 

perinaii  muscle,  gains  the  deep  perineal  space,  pierces  the  anterior  layer  of  the 
deep  perineal  fascia,  and  is  distributed  to  the  dorsum  of  the  penis. 

Crus  Penis  (Dissection  of]  and  Its  Muscle — the  Erector  Penis,  or  IscJiio-cavern- 
OSj{Sf — The  muscle  covers  the  crus.  Cut  through  the  centre  of  the  muscle  in 
the  long  diameter  and  turn  the  two  halves  aside.  Notice  its  extensive  origin  : 
(i)  Tuberosity  of  ischium,  (2)  ramus  of  ischium,  (3)  surface  of  the  crus.  Trace 
the  muscle  up  to  its  insertion  into  the  sides  and  under  surface  of  the  crus  ;  also 
notice  its  nerves  and  vessels.  Now  cut  through  the  thick,  strong  capsule  of  the 
crus  in  its  long  diameter,  and  examine  the  erectile  tissue  of  its  interior.  This 
tissue  is  the  specific  element  of  the  crus,  and  is  called,  in  common  with  the 
remainder  of  the  lateral  pyramid  of  the  penis,  the  corpus  cavernosum.  Observe 
the  strong  origin  of  the  crus  from  the  ischio-pubic  ramus. 

Dissection  of  Accelerator  Urimc  and  the  Bulb. — Depress  the  sound  and  make 
the  bulb,  covered  by  the  accelerator,  stand  out  full.  This  muscle,  as  you  see,  is 
in  the  mid-line,  in  front  of  the  anus.  The  muscle  being  on  the  stretch,  you  will 
now  see  in  the  middle  a  raphe  separating  the  two  halves.  Now  cut,  with  a  very 
sharp  knife,  through  the  center  of  this  raphe  and  turn  the  muscle  outward,  and 
thus  expose  the  bulb.  (Fig.  230.)  Trace  the  muscle  and  note  its  insertions  :  (i) 


334  PRACTICAL  ANATOMY. 

Tlie  lowest  fibres  into  the  triangular  ligament;  (2)  the  middle,  surround  the 
bulb  ;  (3)  tlie  upper  ones  pass  out  across  the  corpus  spongiosum  and  are  inserted 
into  the  dorsum  of  the  penis  and  pubic  bone.  Notice,  also,  the  nerve-supply  to  this 
muscle  from  the  internal  pudic.  Now  cut  through  the  bulb  down  to  the  sound 
and  see  (l)  the  bulbous  part  of  the  urethra  and  (2)  the  erectile  tissue  ;  the  latter 
is  the  specific  element  of  the  bulb,  and,  taken  with  the  remaining  part  of  the 
middle  cylinder  of  the  penis,  is  called  the  corpus  spongiosum.  Notice  the  dense 
fibrous  capsule  of  the  bulb,  derived  from  the  outer  layer  of  the  triangular  liga- 
ment, upon  which  the  bulb  rests.  See  the  nerves  and  vessels  from  the  internal 
pudics. 

Dissection  of  Superficial  Transversus  Penned. — Trace  this  little  muscle  from 
the  tuberosity  of  the  ischium  to  the  central  point  of  the  perineum,  it  being  inserted 
between  the  sphincter  ani  and  the  accelerator.  Notice  the  nerve-supply. 

Dissection  of  the  Penis. — With  the  scissors  cut  through  the  mid-line  of  the 
skin  of  the  scrotum  and  under  part  of  the  penis.  Now.carefully  remove  the  integu- 
ment from  the  entire  organ.  As  stated  above,  the  penis  is  composed  of  three- 
cylinders,  which  converge  from  three  different  sources.  These  three  cylinders 
are  (i)  the  two  corpora  cavernosa  and  (2)  the  urethal  cylinder  or  corpus 
spongiosum,  which  unite  to  form  a  triangular  body  with  three  compartments. 
In  transverse  section.  (Fig.  231.)  See,  now,  that  each  cylinder  has  special  char- 
acteristics, (i)  The  central  cylinder,  resting  on  the  outer  layer  of  the  triangular 
ligament,  begins  in  the  bulb  and  terminates  in  an  expansion,  the  glans  penis, 
which  receives  the  conical  extremities  of  the  lateral  cylinders.  (Fig.  232.)  (2) 
The  lateral  cylinders,  the  corpora  cavernosa,  begin  in  blunt  crura  from  the  ischio- 
pubic  ramus,  are  covered  by  compressor  muscles,  erectores  penis,  and  terminate  in 
pointed  extremities  in  the  distal  expansion  of  the  corpus  spongiosum — the  head  of 
the  penis.  Observe,  also,  that  each  cylinder  has  common  characteristics  :  (i)  a 
fibrous  elastic  envelope  ;  (2)  erectile  tissue.  Lastly,  see  the  middle  cylinder 
traversed  from  end  to  end  by  the  urethra.  Now  cut  down  on  the  sound  and 
expose  the  urethra.  (Fig.  232.) 

The  urethra  is  the  mucous  canal  extending  from  the  bladder  to  the  extremity 
of  the  glans  penis.  In  its  course  it  pierces  the  prostate  from  base  to  apex, 
the  deep  and  superficial  triangular  ligaments  with  the  intervening  compressor 
urethrae  muscle,  and  the  whole  length  of  the  corpus  spongiosum.  It  may  hence 
be  divided  into  three  segments  :  (i)  Prostatic  ;  (2)  membranous  (the  portion  lying 
in  the  space  between  the  two  transverse  triangular  ligaments) ;  and  (3)  spongy. 
(Fig.  232.) 

Having  completed  the  first  stage  of  the  dissection  of  the  pelvic  outlet,  review 
your  work  carefully,  and  see  if  you  have  found  the  following  structures  : 

1.  You  removed  the  skin,  learned  the  boundaries  of  the  pelvic  outlet,  and 
classified  the  same  into  an  anterior  or  perinea/  portion,  and  a  posterior  or  isc/iio- 
rectal  portion. 

2.  You   saw  the  deep  layer  of  the  superficial  fascia, — Colics'  fascia, — having 
two  attachments  :  (i)  To  the  ischio-pubie  ramns  ;  (2)  to  the  triangular  ligament. 

3.  You  located  the  greater  sacro-sciatic  ligament,  cut  the  same,  and  found 
the  main  trunk  of  the  internal  pudic  nerve  with  its  accompanying  vessels.      In 
tliis  locality  you  found  two  nerves  given  off.     One  of  these  you  traced  through 
the  fat  in  the  ischio-rectal  fossa,  in  many  branches,  to   the  corrugator  cutis   ani 
and  external  sphincter  ani  muscles,  and  also  to  the  skin  covering  these  muscles  ; 
this  was  the  inferior  hicinorrlmida/  nerve.     The  other  you  traced,  under  tin.-  name 
of  superficial  peri/teal  nen>e,  to  (i)  the  accelerator,   (2)  tin-   erector    penis,   (3) 
the  superficial  transversus  penn;ei,  and  to  the  skin  covering  these  muscles. 

4.  Then  you  located  the  central  point  of  tlie  perineum,  and  learned  the  muscles 
meeting   there   and   their    nerve-supply  as  follows:  (i)   Accelerator   urin;e  ;   (2) 


THIGH  AND   LEG. 


335 


erector  penis  ;  (3)  superficial  transversus  perinaii ;  (4)  levator  ani.     Nerve-supply, 
the  internal  pudic. 

5.  You  then  located  the  origin  of  the  three  cylinders  of  which  the  penis  is 
composed, — the  central  one  on  the  triangular  ligament  as  the  bulb,  the  lateral 
ones  on  the  ischo-pubic  rami  as  the  crura, — and  you  studied  the  muscles  associ- 
ated with  these  three  cylinders  :  accelerator  urinse  and  erector  penis. 


URETER  -4 

Plica  uretica 

SECTION  OF  BLADDER 


INTERNAL  URINARY  MEATUS 


PROSTATIC  SINUS  WITH  OPENING  OF 
PROSTATIC   GLANDS 

SINUS  POCULARIS 

FOLLICULAR  GLANDS  OF  DORSAL  WALL 


SEPTUM  PECTINIFORME  


THIN  LAYER  OF  CORPUS  SPONGIOSUM 
ORIFICE  OF  COWPER'S  GLAND 


Albuginea  of  corpora  cavernoaa 


FOSSA  NAVICULARIS 


EXTERNAL  URINARY  MEATUS 


SECTION  OF  PROSTATE 
VERUMONTANUM 
EJACLTLATORY  DUCT 
PROSTATIC  GLANDS 


MEMBRANOUS  URETHRA 


SECTION  OF  CORPUS  CAVERNOSUM 


BULBOUS  PORTION  OF  URETHRA 


Mucous  membrane 


j/I(;.  232. THE  MALE  URETHRA,  CLEFT  DORSALI.V  TO  SHOW  VENTRAL  Mucors  WALL. 


6.  You  examined  the  three  component  cylinders  of  the  penis  ;  saw  the 
general  and  special  characters  of  each.  You  saw  each  cylinder  surrounded  by  a 
dense  tunica  albuginea  and  composed  internally  of  erectile  tissue.  You  saw  the 
central  cylinder  traversed  by  a  conduit — the  urethra  ;  you  opened  this  urethra  and 
studied  its  interior.  In  the  cuts  and  in  your  dissections  you  studied  both  the 
transverse  and  longitudinal  sections  of  the  penis. 


336 


PRACTICAL   ANATOMY. 


SECOND  STAGE  IN  DISSECTING  THE  PELVIC  OUTLET. 

Dissect  the  crura  from  the  rami  and  turn  them  upward  over  the  pubic  bone 
and  fasten  them  out  of  your  way.  Cut  the  central  cylinder — the  corpus  spongi- 
osum — off  even  with  the  outer  layer  of  the  triangular  ligament.  Detach  the 
external  sphincter  ani  and  the  two  superficial  transverse  perineal  muscles  at  the 
central  perineal  point.  Then  your  field  will  look  like  the  leftside  of  figure  233. 

The  triangular  ligament  (Fig.  233)  occupies  the  space  under  the  pubes.  It 
consists  of  two  layers,  superior  and  inferior,  also  called  superficial  and  deep  tri- 
angular ligaments,  between  which  are  found  :  (i)  The  membranous  urethra  (Fig. 
232)  ;  (2)  the  duct  of  Cowper's  gland  perforating  the  superficial  triangular 
ligament  (Fig.  233)  and  opening  into  the  bulbous  urethra  (Fig.  232);  (3)  the 
dorsal  nerves  and  vessels  of  the  penis  perforating  the  suspensory  ligament  of  the 
penis  and  supplying  the  back  of  the  penis  (Fig.  233);  (4)  the  deep  transversus 
perinaei  or  compressor  urethrae,  the  muscle  of  Guthrie.  (Fig.  234.) 

The  above  structures  are  seen  on  removing  the  inferior  layer  of  the  triangular 


Subpubic  ligament  with  aperture  for 
dorsal  vein  of  the  penis 

Apertures  for  dorsal  artery  and  ( 
nerve  of  the  penis  \ 


Crus  penis 
Aperture  for  artery  of  corpus 

cavernosum 

Superficial  triangular  ligament 
Ischio-caveruosus,  or  erector  penis 
Aperture  for  artery 

to  bulb 

TJrethral  aperture 
Aperture  for  Cow- 
per's duet 
Position  of  bulb 


Apertures  for  super- 
ficial perinceal 
vessels  and  nerve 


Fascia  of  Colles, 
turned  backwards 


DORSAL  NERVE 
Anterior  layer  of  triangular 

ligament 
Dorsal  artery  of  penis 

Deep  triangu- 
lar ligament 
Artery  of  carpus 
cavernosum 

Artery  to  bulb 

J'n</i<'  reins 

*—  DORSAL  NERVE 
—  POSITION  OF  COWPER'S 
GLAND 

Internal  pudic  artery 


Posterior  border  of 
permaeal  ledge 
(junction  of  trian- 
gular ligaments 
with  fascia  of 
(Jolles) 


FIG.  233. — DIAGRAM  OF  THE  SUPERFICIAL  AND  DEEP  TRIANGULAR  LKJA.MI-N  is. 


ligament.  (Fig.  233.)  Now  study  the  attachments  of,  and  the  foramina  in,  the 
triangular  ligament  and  compare  your  work  with  figure  233. 

You  will  now  dissect  the  ischio-rectal  fossa.  You  have  traced  the  inferior 
haemorrhoidal  vessels  through  the  fatty  mass  of  this  fossa  to  the  rectum  and  anus. 
You  will  now  remove  the  fat  and  study  the  geometrical  parts  of  this  region. 

'I'lic  outer  wall  \?>  formed  by  the  obturator  interims  muscle  and  the  innominate 
bone.  This  muscle  is  covered  by  a  dense  fascia  of  the  same  name.  This  fascia 
splits  to  form  a  canal  (Alcock's)  in  which  are  the  internal  pudic  vessels  and 
nerve.  TIic  inner  wall  of  the  ischio-rectal  fossa  is  formed  by  the  levator  ani  and 
coccygeus  muscles.  These,  as  you  will  see,  embrace  the  rectum  and  give  it  sup- 
port. The  levator  ani  muscle  arises  from  the  white  line.  This  line  extends  from 
the  spine  of  the  ischium  to  the  pubic  bone.  The  obturator  fascia  delaminutcs  at 
the  white  line,  and  gives  origin  to  the  levator  ani  muscle  in  the  split  between  the 
upper  and  lowrr  branches  into  which  it  divides.  The  apex,  then,  of  the  fossa  is 
at  the  white  line.  The  boundaries,  as  you  will  now  see  them  on  your  work,  of 
tin-  inlet  of  the  fossa  are:  (i)  The  external  sphincter  ani;  (2)  the  superficial 
transversus  perinaei  ;  (3)  the  greater  sacro-sciatic  ligament  ;  (4)  the  glutens  maxi- 
inus  muscle;  (5)  the  tubers  of  the  ischium.  The  base  of  the  fossa  is  the  skin 


THIGH  AND  LEG. 


337 


and  fasciae  covering  the  inlet.  The  fossa  extends  in  an  upward  direction  to  the 
pubic  bone  ;  in  a  backward  direction  to  the  sacrum,  forming  the  anterior  and 
posterior  recesses  of  Morris.  In  liberating  pus  in  this  fossa,  cut  through  the  base  ; 
then  lay  your  knife  aside  and  continue  the  operation  with  a  blunt  instrument. 

1.  Give  tlie  shape  of,  and  tell  ivJiat  yon  mean  by,  the  pelvic  outlet. 

It  is  lozenge-shaped,  and  is  the  space  bounded  by  the  pubic  arch  above,  the 
coccyx  below,  and  the  greater  sacro-sciatic  ligament,  tuberosity  of  the  ischium, 
and  ischio-pubic  ramus  laterally. 

2.  Give  the  subdivisions  of  this  space,  and  tell  zvhere  the  boundary -line  between 
the  two  is  located. 

A  line  from  tuberosity  to  tuberosity  of  the  ischium  divides  the  space  into  an 
anterior  triangle,  the  perineum,  and  a  posterior  triangle,  the  ischio-rectal  fossa. 


P'IG.  234. — MUSCLE  OF  GUTHRIE. 
I.    Bulbo-cavernosus    (accelerator    urinre)    muscle. 
2.   Muscle  of  Guthrie  (transversus  perinaei  profun- 
dus).      3.    Superficial  transverse  muscle.     4.  Ex- 
ternal sphincter  ani.     5.    Levator  ani. 


FIG.  235. — MUSCLE  OF  GUTHRIE  AND  WILSON. 

i.  Bulb  of  urethra.  2,  2.  Muscle  of  Guthrie 
(transversus  perinsei  profundus).  3.  Muscle  of 
Wilson.  4.  Transversus  perin<iei  superficialis. 
5.  External  sphincter  ani.  6.  Levator  ani. 


3.  Give  the  contents  of  the  ischio-rectal  fossa. 

It  contains  the  rectum  and  the  fossa  on  each  side  of  the  rectum,  called  ischio- 
rectal  fossa. 

4.  Give  the  geometrical  parts  of  this  fossa  and  the  importance  you  attach  to 
each  part. 

(i)  Apex,  at  the  white  line,  the  origin  of  the  levator  ani ;  (2)  base,  the  skin 
and  fasciae,  between  anus  and  tuber  of  ischium  ;  (3)  outer  wall,  the  obturator 
internus,  Alcock's  canal  and  contents  ;  (4)  inner  wall,  the  levator  ani  and  coccy- 
geus  muscles  covered  by  the  anal  fascia  ;  (5)  an  anterior  or  pubic  recess  ;  (6)  a 
posterior  or  sacral  recess. 

5.  Where  is  Alcock's  canal,  how  is  it  found,  and  what  are  its  contents  ? 

It  is  in  the  outer  wall  of  the  ^chic-rectal  fossa,  in  a  delamination  of  the  ob- 
turator fascia  ;  it  contains  the  internal  pudic  vessels  and  nerve  and  extends  from 
the  lesser  sacro-sciatic  foramen  to  the  deep  triangular  ligament. 

6.  Name  the  contents  of  the  ischio-rectal  fossa. 

The  fossa  contains  fat  and  connective  tissue,  in  which  are  embedded  the 
inferior  haemorrhoidal  nerves  and  vessels.  On  dissection  you  will  see  these 
structures  crossing  the  fossa  to  supply  the  rectum. 


PRACTICAL    ANATOMY. 


7.  Xame  tlic  structures  tJiat  meet  at  tlie  central  point  of  tJic  perineum. 

The  accelerator  urinae  and  bulb.  The  external  sphincter  ani.  The  superfi- 
cial trans  versus  perinaei.  The  rectum  and  labia  majora.  The  triangular  liga- 
ment and  labia  majora.  The  fascia  of  Colles.  The  superficial  perineal  space. 

8.  What   is  the  importance  of  the  fascia  of  Colles  in   extravasation  of  urine 
through  the  bulb  ? 

This  fascia  limits  its  extension  laterally  and  posteriorly,  since  it  is  attached 
both  to  the  ischio-pubic  ramus  and  lower  part  of  the  triangular  ligament. 

9.  Give  the  derivation  of  the  superior  layer  of  the  triangular  ligament. 
It  is  a  continuation  of  the  obturator  fascia. 

i  o.  Define  the  anal  fascia. 

It  is  a  division  of  the  obturator  fascia  that  covers  the  under  surface  of  the 
levator  ani  muscle. 

I  I .   Name  the  several  modifications  of  the  pelvic  fascia. 

(i)  Iliac  ;  (2)  obturator  ;  (3)  white  line  ;  (4)  Alcock's  canal  ;  (5)  anal  fascia  ; 
(6)  recto-vesical  fascia  ;  (7)  triangular  ligament ;  (8)  pubo-prostatic  ligament. 


EJAOULATORY  DUCT 
SINUS  POCULARIS 


VERUMONTANUM 
ORIFICE  OF  EJACULATORY  DUCT 


AMPULLA  OF  VAS  DEFERENS 


UNION  OF  VESICULA  WITH  VAS 


EJACULATORY  DUCT  ENTERING 
PROSTATIC  FISSURE 


PROSTATE 


MEMBRANOUS  URETHRA  - 


ORIFICE  OF  SINUS  POCULARIS 
LOWER  END  OF  VERUMONTANUM 

VESICULA  SEMINALIS 


FIG.  236.— VASA  DEKERENTIA  AND  VESKTI.V.  SKMINUIS.     (After  Sappey.) 

The  Base  of  the  Bladder  and  Seminal  Vesicles.— Having  thoroughly 
studied  the  perineum  and  ischio-rectal  fossa,  make  a  dissection  to  show  (i)  the 
membranous  urethra,  (2)  the  prostate  gland,  (3)  the  lower  part  of  the  rectum, 
(4)  the  vesiculae  seminales,  (5)  the  base  of  the  bladder,  in  the  following  manner 
(turn  to  Fig.  229) :  Cut  the  external  sphincter  ani  and  pull  the  rectum  back- 
ward and  downward  over  the  coccyx.  This  will  put  the  levator  ani  on  the 
stretch.  Now  divide  the  levator  ani  near  the  white  line — its  origin,  as  you  will 
remember.  Now  you  will  see  in  the  mid-line  (i)  the  membranous  urethra,  with 
Cowper's  gland  on  each  side;  (2)  the  prostate  gland,  receiving  at  its  central  part 
the  ejaculatory  duct  of  the  seminal  vesicles  ( l-'ig.  236);  (3)  the  base  of  the  bladder, 
occupied  by  fatty  conneetive  tissue,  in  which  you  will  find  a  remarkable  plexus 


THIGH  AND   LEG.  339 

of  veins — the  vesico-prostatic.  A  small  amount  of  work  with  the  forceps  will 
expose  to  view  all  the  above  structures. 

1 .  Describe  the  prostate  gland. 

It  is  in  front  of  the  neck  of  the  bladder,  the  part  resting  on  the  bladder 
being  the  base.  (Fig.  232.)  The  posterior  surface  is  on  the  rectum.  The  ante- 
rior surface  is  behind  the  symphysis.  The  apex  reaches  the  triangular  ligament. 
It  has  three  lobes.  You  will  see,  between  the  lateral  lobe  and  the  middle  lobe, 
the  ejaculatory  duct.  The  prostate  is  traversed  by  the  urethra  and  ducts  just 
mentioned.  The  gland  is  surrounded  by  a  firm  capsule.  Its  substance  is  gland- 
ular and  muscular,  and  not  easily  torn,  as  is  the  spleen. 

2.  Describe  the  vesico-prostatic  pie. rns. 

This  is  now  easily  shown.  It  consists  of  engorged  veins  which  surround  the 
neck  and  base  of  the  bladder  and  the  prostate,  just  mentioned.  The  dorsal  vein 
of  the  penis  passing  close  under  the  subpubic  arcade  discharges  into  this  plexus. 
(Fig.  233.)  Behind  this  plexus  is  the  haemorrhoidal  plexus.  The  two  plexuses 
communicate  very  freely. 

3.  Give  function  of  vesic  nice  seminales.     (Fig.  236.) 

They  act  as  a  reservoir  for  the  semen,  just  as  the  gall-bladder  is  a  receptacle 
for  bile.  The  vas  deferens  brings  semen  from  the  testicle,  as  the  hepatic  duct 
brings  bile  from  the  liver.  The  seminal  duct  and  vas  come  together  to  form  the 
excretory  duct,  just  as  the  cystic  and  hepatic  unite  to  form  the  common  bile 
duct.  The  vas  deferens  is  two  feet  in  length. 

4.  Name  tlie  structures  pierced  by  the  male  urethra. 

(i)  The  prostate  from  base  to  apex;  (2)  the  deep  and  superficial  triangular 
ligaments  ;  (3)  the  compressor  urethrae  muscle  (Outline's  muscle) ;  (4)  the  corpus 
spongiosum. 

5.  Wliat  is  the  average  length  of  the  male  urethra  / 

It  is  about  six  and  one-half  inches  long.  Its  length  is  increased  in  senile 
hypertrophy  of  the  prostate. 

6.  Give  the  length  of  the  pro  static  urethra  and  tell  zvhat  you  found  in  the  same. 
Its  length  is  one  and  one-fourth  inches.     In  this  part  of  the  urethra  we  found  : 

(i)  The  sinus  pocularis,  or  uterus  masculinus,  believed  to  be  homologous  to  the 
uterus  of  the  female  ;  (2)  the  openings  for  the  seminal  ejaculatory  ducts  ;  (3)  the 
orifices  for  the  prostatic  glands. 

7.  Name  and  locate  the  dilated  parts  of  the  spongy  portion  of  the  urethra. 

(i)  The  pars  bulbosa  in  the  bulb,  one  inch  in  length  ;  (2)  the  fossa  navicularis, 
one  inch  in  length,  situated  in  the  glans  penis. 

8.  Locate  the  penile  angle. 

It  is  about  two  inches  in  front  of  the  external  layer  ot  the  triangular  ligament. 

9.  Describe  the  blood-supply  to  and  from  the  penis. 

A  distinction  must  be  made  between  the  superficial  circulation  and  the  deep  : 

(1)  The  circulation  in  the  retractile  or  loose  covering,  or  the  superficial   circu- 
lation, reaches  the  penis  by  (#)  the  external  pudic  artery,  a  branch  of  the  common 
femoral  artery;  (£)  the  superficial  perineal,  a  branch  of  the  internal  pudic;  (c] 
the  superficial  branch  of  the  dorsal  artery  of  the  penis.      The  blood  from  this 
superficial  circulation  is  collected  in  one  or  two  rather  large  superficial  veins,  and 
conveyed  by  them  to  the  femoral  vein  and  its  large  tributary,  the  long  saphenous. 

(2)  Blood  reaches  the  penis  proper  by  arteries  to  the  bulb  and  corpus  cavernosum. 
These  vessels  are  branches  of  the  internal  pudic  artery.    They  are  given  off  from 
this  artery  in  the   space  between  the   superficial  and   deep  triangular  ligaments. 
(Fig.  233.)     They  pierce  the  superficial  triangular  ligament  preparatory  to  sup- 
plying these  parts.      The  dorsal  artery  of  the  penis  (Fig.  233)  also  supplies  the 
deep  parts  of  the  penis.      Blood  from  this  region  is  returned  to  the  venous  circu- 
lation by  two  routes  :  (a)  By  the  dorsal  vein  of  the  penis  ;  (/>)  by  the  veins  that 


340  PRACTICAL  ANATOMY. 

accompany  the  arteries  to  the  corpora  cavernosa  and  corpus  spongiosum.  The 
dorsal  vein  passes  under  the  pubic  arch  and  is  tributary  to  the  vesico-prostatic 
plexus,  at  the  base  and  sides  of  the  bladder.  The  other  veins  accompany  their 
arteries  and  become  tributary  to  the  internal  iliac  vein. 

10.  Describe  the  nerve-supply  of  the  penis. 

The  erectile  bodies  receive  nerves  from  the  dorsal  nerve  of  the  penis  ;  the 
superficial  perineal  and  sympathetic  filaments  from  the  hypogastric  plexus.  The 
skin  receives  sensory  branches  from  the  genito-crural  and  superficial  perineal. 


THE  FEMALE  PELVIC  OUTLET. 

The  surgical  importance  of  the  female  perineum  will  warrant  a  thorough 
consideration  of  its  dissection  in  this  book.  The  homologies  are  so  striking  that 
some  of  our  best  text-books  on  anatomy  seem  content  to  refer  the  student  to  the 
male  perineum  to  gain  his  conception  of  the  structure  of  the  female  peri- 
neum. To  my  mind  this  is  a  most  neglectful  practice,  since  the  desideratum  is 
a  practical  one,  involving  acquisition  of  knowledge  pending  operative  procedure, 
instead  of  a  knowledge  in  the  direct  line  of  morphological  research.  Would  the 
student  be  competent  to  treat  the  male  urethra,  who  had  studied  only  the  clitoris 
from  an  anatomical  standpoint  ?  Still,  the  penis  is  homologous  to  the  clitoris,  and 
in  the  male  the  urethra  occupies  the  entire  length  of  the  central  cylinder  of  the 
penis.  Would  the  student  be  competent  to  remove  a  diseased  testicle,  whose 
anatomical  knowledge  was  all  in  homologies?  Again,  my  experience  teaches 
me  that  medical  students  look  upon  the  outlet  of  the  female  pelvis  not  from  the 
standpoint  of  the  morphologist.  It  requires  study  and  practice  to  see  in  the  fore- 
skin, the  labia  minora  ;  in  the  scrotum,  the  labia  majora  ;  in  the  accelerator 
urinae,  the  sphincter  vaginae  ;  in  the  bulb  of  the  urethra,  the  bulb  of  the  vagina  ; 
in  the  spermatic  cord,  the  round  ligament  of  the  uterus  ;  in  the  uterus  mascu- 
linus  of  the  prostatic  urethra,  the  uterus  of  the  female  ;  in  the  testicle  of  the 
male,  the  ovary  of  the  female. 

The  repair  of  the  female  perineum  is  seconded  in  point  of  frequency  only 
by  extirpation  of  diseased  ovaries  and  tubes  ;  in  comparison  to  these  operations 
on  the  female,  seen  thousands  of  times  by  our  students,  I  would  ask  our  seniors. 
How  many  operations  on  the  male  perineum  have  you  witnessed  ?  How  many 
castrations  have  you  been  party  to  ?  A  student  may  be  expert  in  introducing* 
the  catheter  into  the  male  urethra,  but  without  special  knowledge  he  will  be  ai 
ignominious  failure  when  he  attempts  to  perform  this  operation  on  the  female.  A 
knowledge  of  the  specific  anatomy  of  the  female  generative  organs  must  In- 
acquired  by  dissection  ;  homological  studies  are  most  useful  and  most  necessary 
adjuncts. 

Examine  before  making  any  incisions  : 

1.  The  mons  veneris,  or  mons  pubis,  the  fatty  elevation  covered  with  crisp 
hair,  surmounting  the  pubes. 

2.  The  vulva  is  a  collective   noun  by  which  all   the  external    genitals  of  the 
female,  except  the  mons  pubis,  are  designated. 

3.  The  clitoris   is   an   erectile   structure   analogous  to  the  penis.      Its   free 
extremity  is  the  glans.      It  has  ;i  suspensory  ligament  and  erector  muscles.      On 
each  side  it  has  a  cms  originating  from  the  ischio-pubic  ramus. 

4.  The  major  labia   are   homologous  to  the  scrotum.      They  are  cleft  alon;^ 
the  mid  !in«-(rima  pudendi).    They  extend  from  the  mons  to  the  tendinous  centre 


THIGH  AND   LEG.  341 

of  the  perineum.     They  flatten  out  posteriorly  into  the  smooth  covering  of  the 
perineum.      Their  junction  here  is  called  posterior  commissure. 

5.  The  minor  labia  are  homologous  to  the  prepuce.     They  are   cutaneous 
folds.     They  have  neither  hair  nor  fat.      In  the  adult  they  are  concealed  by  the 
major  labia  ;   not  so  in  the  foetus.      They  are  connected  posteriorly  by  the  four- 
chette. 

6.  Examine  carefully  the  vestibule.     This  is  a  guide  to  the  meatus  urin- 
arius  in  using  the  catheter.      It-  opens  into   the   meatus  and  extends  from  this 
opening  to  the  clitoris. 

7.  The  meatus  urinarius  externus  is  the  distal  end  of  the  urethra.     It  is 
nearly  an  inch  from  the  clitoris.      Introduce  a  catheter  into  the  bladder  and  feel 
the  urethra  on  the  anterior  vaginal  wall,  in  the  mid-line  and  1.5  inch  in  lerfgth. 

8.  The  vaginal  orifice  lies  in  the  mid-line.      It  is  narrowed  by  the  hymen  in 
the  virgin,  and  surrounded  by  the  remains   of  the  hymen  in  females  who  have 
borne  children.      Its  homologue  would  be  artificially  produced  by  a  vertical  slit 


ISCHIO-HUBIC  ARCH 


CRUS  CLITORIDIS   WITH 
ISCHIO-CAVERNOSUS 


BULBO-CAVERNOSUS 
COVERING  BULBU3 
YESTIBULI 


Superficial  trian- 
gular ligament 


GLANS  CLITORIDIS 
WITH  PREPUCE 


PARS  INTERMEDIALIS 
Mucous  membrane 
*%  of  vestibule 

—  MEATUS  URINARIUS 


BULBUS  VESTIBULI 


GLAND  OF  BARTHOLIN 


Sphincter  ani 


FIG.  237. — DIAGRAMMATIC  REPRESENTATION  OF  THE  PERINEAL  STRUCTURES  IN  THE  FEMALE. 


through  the  bulb  of  the  male  urethra  ;  the  two  parts  of  the  accelerator  urinae 
would  then  be  homologous  to  the  sphincter  vaginae,  and  the  erectile  tissue  of  the 
bulb  to  the  bulbi  vestibuli. 

9.  "The  Hymen  "  (Fig.  238),  says  Morris,  "  has  been  a  subject  of  much 
speculation  among  the  learned  and  unlearned  of  all  ages.  Its  very  existence 
was  at  one  time  denied  by  many  great  authorities."  Failure  to  find  this  in 
careful  examination  of  several  hundred  female  foetuses  and  young  babes  has 
caused  me  to  ask  if  it  be  possible  that  the  hymen  is  absent  in  females  until  the 
age  when  other  pubal  changes  occur.  The  remains  of  the  hymen  are  called  car- 
uncnlie  myrtifonnes.  They  surround  the  entrance  to  the  vagina. 

Having  located  the  foregoing  nine  structures,  and  thoroughly  learned  both 
their  function  and  homologies,  where  the  latter  exist,  you  are  now  ready  to  begin  a 
careful  dissection  of  t\\e  female  pelvic  outlet.  Remember,  there  is  no  difference  in 
the  posterior  triangular  region — the  ischio-rectal  fossa — in  the  sexes.  The  differ- 
ences will  all  be  found  in  the  anterior,  or  perineal  region. 


342 


PRACTICAL  ANATOMY. 


Dissection. — Place  the  subject  in  the  proper  lithotomy  position,  as  described 
previously  for  dissecting  the  male  perineum.  Thoroughly  remove  all  pubic  hair. 
Find  the  following  structures  and  dissect  them  in  this  order  : 

1.  Tlie  clitoris,  homologous  to  the  penis. 

2.  The  labia  uiajora,  homologous  to  the  scrotum. 

3.  The  bulbo-cavernosus,  homologous  to  the  accelerator. 

4.  The  bnlbi  vcstibuli,  homologous  to  the  bulb  of  the  urethra. 

5.  The  gland  of  Bartholin,  homologous  to  Cowper's  gland. 

6.  The  sphincter  ani,  the  superficial  transversus  perincei,  and  superficial  part  of 
the  triangular  ligament. 

The  Clitoris. — The  clitoris  is  homologous  to  the  penis.  Its  size  is  often 
underestimated,  because  the  foreskin — the  labia  minora — binds  it  clown  so  you  are 


MONS  VENERIS   — 


GUNS  CLITORIDIS  — 


MEATUS  URINARIUS  IN 
VESTI8ULAR  SPACE 


CORPUS  CLITORIDIS 

LABIUM  MAJUS 
LABIUM  MINUS 

HTM  EM 


ANUS 


FIG.  238. — EXTERNAL  GENITALS  OF  THE  VIRGIN,  \VITH  DIAPIIRACM  \  1 1<    HY.MIV     (Sappey.) 


able  to  see  only  the  distal  end,  called  the  glans.  In  the  pom's  the  prq> 
covers  the  glans  and  terminates  below  in  a  frenum  ;  in  the  clitoris  the  prepuce 
terminates  in  the  two  elongated  labia  minora,  owing  to  the  vertical  cleft  of  the 
vaginal  orifice.  To  dissect  properly  this  organ,  grasp  the  glans  in  the  forceps  of 
your  left  hand,  and,  with  the  scissors  in  your  right  hand,  cut  the  skin  along  the 
dorsum  of  the  clitoris  for  an  inch  upward.  Then  you  can  see  the  corona  glandi.-' 
and  the  glans  clitoridis  in  full  view.  Next  remove  carefully  the  skin  from  tin- 
two  crura  along.the  ischio-pubic  ramus.  You  will  find  these  crura  covered  by  a 
nuiM-lc,  the  erector  clitoridis,  homologous  to  the  erector  penis. 

Kemove  the  skin  from  the  labia  majora  and  trace  the  crescentic  muscular  fibres 
of  the  bulbo-cavernosus  muscle  around  the  orifice  of  the  vagina.  This  is  tin- 
sphincter  muscle  of  the  vagina.  The  transversus  perina-i  and  sphincter  ani  an 


THIGH  AND   LEG. 


343 


the  same  as  in  the  male.  The  nerve-  and  blood-supply  are  precisely  the  same. 
The  deep  perineal  fascia  transmits  the  urethra.  It  is  smaller  than  in  the  male, 
on  account  of  the  vagina.  (See  blood-supply  on  page  339.) 

The  perineal  body  (Fig.  239)  occupies  the  space  between  the  lower  part  of 
the  vagina  and  the  rectum.  It  has  a  base,  covered  by  skin,  and  an  apex  between 
the  termini  of  its  anterior  and  posterior  surfaces.  From  side  to  side  it  extends 
from  tuber  to  tuber  of  the  ischium.  Its  posterior  surface  lies  in  front  of  the 
anterior  wall  of  the  rectum  ;  its  anterior  surface  lies  behind  the  posterior  vaginal 
wall.  Into  it  are  attached  all  the  muscles  of  the  central  perineal  point  or  tendon  : 
(i)  The  external  sphincter  ani  ;  (2)  the  superficial  transversus  perinaei ;  (3)  the 


VESICAL  WALL 

CAVITY  OF  BLADDER 

Prevesical  fat 


Deep   transver- 
BUB  perinaei 


LABIUM  MAJUS 
TTnstriped  muscular  fibre 


URETHRA 
LABIUM  MINUS 
Unstriped  muscular  flbre 


ANUS 

Internal  sphincter  ani 
Part  of  external  sphincter  ani 


Vessels 


RECTUM 

COCCYX 

Eecto-cocey- 
geal  muscle 

POSTERIOR  LIP  OF  OS 

UTERI 
ANTERIOR  LIP 

VAGINA 

External 
sphincter  ani 

Internal 
sphincter  ani 


VAGINAL  ORIFICE 

FIG.  239. — SECTION  OF  THE  FEMALE  PELVIS.     (After  Henle.) 


This  perineal  body  is  strong;  it  owes  its  strength  to  elastic 
The  perineal  body  is  about  an  inch  and  a  half  in  length  from 


sphincter  vaginae, 
connective  tissue, 
before  backward. 

The  glands  of  Bartholin  probably  represent  Cowper's  glands  in  the  male, 
but  are  more  superficially  placed.  They  are  two  little  racemose  glands,  about 
a  third  of  an  inch  long,  situated  one  on  each  side  beneath  the  lateral  wall  of  the 
vestibule  and  behind  the  bulbi  vestibuli.  The  duct,  about  three-quarters  of  an 
inch  in  length,  opens  immediately  in  front  of  the  vaginal  orifice  opposite  its 
meridian. 

Locate  the  vagina  by  superior  and  inferior  limitations. 


344  PRACTICAL  ANATOMY. 

It  is  limited  inferiorly  by  the  introitus  vaginae  at  the  vestibule,  and  superiorly 
by  its  junction  with  the  cervix  uteri. 

Define  and  locate  tlie  utcro-vaginal  forni.v. 

It  is  the  highest  part  of  the  vagina  ;  a  space  surrounding  that  part  of  the 
cervix  uteri  within  the  vagina,  and  formed  by  the  reflexion  of  the  vaginal 
mucous  membrane  on  to  the  cervix.  The  vaginal  passage  extends  upward  and 
backward.  Its  long  axis  extended  would  pass  through  the  upper  segment  of 
the  sacrum. 

What  arc  tJic  anterior  relations  of  the  vagina  / 

It  is  in  close  relation  with  the  urethra  and  bladder.  The  ureters  open  into 
the  posterior  wall  of  the  bladder,  anterior  to  the  vagina,  and  about  an  inch  below 
the  lowest  part  of  the  cervix  uteri.  There  is  a  large  amount  of  connective  tissue 
between  the  anterior  wall  of  the  vagina  and  the  bladder  and  urethra. 

Describe  the  posterior  relations  of  the  vagina. 

The  vagina  is  in  relation  posteriorly  with  the  rectum.  Intervening  between 
the  rectum  and  posterior  wall  of  the  vagina  from  above  downward  are  (i)  the 
peritoneal  cul-de-sac  of  Douglas  ;  (2)  subperitoneal  connective  tissue  ;  (3)  the 
perineal  body. 

Describe  the  lateral  relations  of  t/ie  vagina. 

(i)  The  vaginal  branch  of  the  uterine  artery — the  uterine  being  a  branch  of 
the  internal  iliac  ;  (2)  a  plexus  of  veins,  lying  at  the  base  of  the  broad  ligament 
of  the  uterus,  communicating  with  the  haemorrhoidal,  and  tributary  to  the  internal 
iliac  vein. 

Hoiv  is  the  vaginal  inlet  narrowed  ? 

By  the  action  of  the  sphincter  vaginae,  the  levator  ani,  and  engorgement  of 
the  erectile  tissue  of  the  inlet,  called  the  bulbi  vestibuli. 

Describe  the  structure  of  the  vaginal  wall. 

It  is  composed  of  three  coats  :  (i)  An  outer  fibrous  coat,  a  derivative  of  the 
recto-vesical  fascia.  In  this  coat  you  will  find  in  some  cases  a  beautiful  plexus 
of  veins.  (2)  A  muscular  coat,  consisting  of  outer  longitudinal  fibres  and  an 
inner  layer  of  circular  fibres.  The  muscular  coat  consists  of  unstriped  fibres. 
(3)  A  mucous  coat,  highly  elastic,  and  continuous  above  with  the  mucous  mem- 
brane of  the  uterus,  and  below  with  that  of  the  vulva. 

Describe  tlie  blood-supply  of  the  vagina. 

The  arteries,  derived  from  the  internal  iliac,  from  the  inferior  branch  of  the 
uterine,  and  from  the  external  pudic  branch  of  the  common  femoral  artery,  lie 
along  the  lateral  part  of  the  vagina  and  divide  into  anterior  and  posterior  branches 
for  the  supply  of  the  anterior  and  posterior  surfaces  respectively.  The  veins  follow 
the  course  of  the  arteries,  form  a  rich  plexus  between  the  inner  and  middle  coats, 
and  finally  become  tributary  to  the  internal  iliac  vein.  The  nerve-supply  of  the 
vagina  is  from  the  hypogastric  plexus,  internal  pudic  nerve,  and  the  fourth 
sacral. 


POSTERIOR   PART   OF  SHOULDER,   ARM,    FOREARM,   AND 

HAND. 


Dissection. — Locate — (i)  the  acromion  process  dx\&  spine  of  the  scapula  ;  (2) 
the  inner  and  outer  Jin  in  cral  condyles  ;  (3)  the  olecranon  process  of  the  ulna;  (4) 
the  head  of  the  radius  ;  (5)  the  inferior  outer  border  of  the  clavicle  ;  (6)  the  a.vil- 


Coraco-acromial      Pectoralis 

ligament  minor  Omo-hyoid  and  the  transverse  ligament 


AXILLARY  BORDER 


Teres  major 


SUPERIOR  ANGLE 


Rhomboideus 
minor 


Rhomboideus 
major 


VERTEBRAL 
BORDER 


INFERIOR  ANGLE 


Latissimus  dorsi 


IMC.  240. — THE  LKI  r  SCAPULA.     (Dorsal  surface.) 

lary  border  of  the  scapula  ;   (7)  the  superior  border  of  the  scapula  ;  (8)  the  greater 
and  lesser  titbcrosities  of  the  hit  merits  ;  (9)  the  olecranon  fossa  ;  (10) i  the  Jilnar  and 
radial  styloid  processes  ;    (ii)  the  radio-carpal  articulation  ;   (i  2)  the  metaearpo- 
23  345 


346 


PRACTICAL  ANATOMY. 


plialangeal  articulation  ;  (13)  the  phalangcal  articulations;  (14)  the  clefts  of  tlic 
fingers  ;  (15)  the  thcnar  and  JiypotJicnar  eminences. 

Incisions. — (i)  From  the  acromion  process  to  the  end  of  the  middle  finger  ; 
(2)  from  the  outer  one-third  of  the  clavicle  to  the  acromion  process,  thence  along 
the  scapular  spine  ;  (3)  from  one  condyle  to  the  other. 

Dissection  (Figs.  241  and  242). — Carefully  remove  the  skin  and  find  the  : 

1 .  Radial  nerve  distributed  to  three  and  one-half  fingers  dorsally. 

2.  Ulnar  dorsal  branch  to  one  and  one-half  fingers  dorsally. 

3.  External  cutaneous,  a  branch  of  the  musculo-spiral  nerve. 

4.  Internal  cutaneous  nerve  from  the  inner  cord  of  the  brachial  plexus. 


INTERNAL 
CUTANEOUS  OF 
MUSCULO- 
SPIRAL 


INTERS  A  L 
CUTANEOUS 


PALMAR 

CUTANEOUS  OF 

MEDIAN 
PALMAR 

CUTANEOUS  OF 

ULNAR 


SUPRA- 

ACROMfAL 


CIRCUMFLEX 


TWIG  OF 
INTERNAL 

CUTANEOUS 

EXTERNAL 
CUTANEOUS  OF 

MUSCULO- 

SPIRAL 


SUPRA- 

ACROMIAL 


FLEX 


MUSCULO- 
CUTANEOUS 


EXTERNAL 
CUTANEOUS 

OF 

MUSCULO- 
SPIRAL 

MUSCULO- 
CUTANEOCii 


RADIAL 


PALMAR 

CI'TANEOUS 
OF  RADIAL 


FIG.  241. — DISTRIBUTION  OK  CUTANEOUS  NK.KVKS  ON  TIIK  ANTKRIOR  AND  POSTERIOR  ASPECTS 

OF  THE  SUPERIOR  EXTRKMITV. 


5.  Lesser  internal  cutaneous  or  the  nerve  of  Wrisberg. 

6.  Internal  cutaneous  nerve,  a  branch  of  musculo-spiral. 

7.  Cutaneous  branches  of  the  circumflex  nerve  to  skin  of  deltoid. 

8.  Supraacromial,  a  descending  branch  of  the  cervical  plexus. 

9.  Intercosto-humeral  nerve — the  lateral  cutaneous   branch   of  the  second 
intercostal  nerve. 

General  directions  only  can  be   give 
(i)   Keep   close   to  the  skin   when  you 

Mar- in  ally,  you  will  see  the  name  of  the  nerve,  which,  having  found,  take  your 
forceps  and  search  in  the  superficial  fasdu  of  the  region  until  you  find  the  nerve. 


for  doing  this  cutaneous  dissection  : 
remove  it.     (2)    Consult   the    figures. 


SHOULDER,  ARM,  FOREARM,  HAND.— POSTERIOR  PART.      347 

(3)   Then  lift  the  nerve  on  your  finger  and  follow  the  same  by  dividing  the'con- 
nective  tissue  in  the  direction  of  the  branches  given  off. 

Remember  that  the  circumflex  nerve  sends  its  cutaneous  branches  to  the  skin 
over  the  insertion  of  the  deltoid,  according  to  Hilton's  law.  (Fig.  241.)  The 
musculo-cutaneous  nerve  sends  a  cutaneous  branch  to  supply  the  skin  over  the 
insertion  of  the  supinator  longus,  according  to  the  same  law,  since  this  muscle 
is  one  of  the  forearm  flexors  and  is  supplied  by  the  musculo-cutaneous.  The 


DORSAL  BRANCH 
OF  ULNAR 


BRANCH  OF 
MEDIAN 
NERVE 


BRANCH  OF  MUSCULO-SPIRAL 


RADIAL  NERYE 


FIG.  242. — A  DISSECTION  OF  THE  CUTANEOUS  NERVES  ON  THE  DORSAL  ASPECT  OF  THE 

HAND  AND  FINGKRS.     (H.  St.  J.  B.) 
The  branches  of  the  median  nerve  are  shown  in  black. 


distribution  of  the  radial  nerve  is  explained  in  the  same  way.      You  will  note  that 
the  cutaneous  nerves  divide  into  numerous  small  branches.     (Fig.  242.) 

The  deep  fascia  is  quite  heavy  below  the  elbow,  but  thin  above  the  elbow. 
Opposite  the  wrist  it  takes  the  name  posterior  annular  ligament.  Notice  in  figure 
243 — that  the  muscles  all  become  tendinous  before  they  reach  this  ligament. 
Remove  the  deep  fascia  as  in  the  figure.  "Dorsal  fascia"  is  the  name  for  the 
deep  fascia  on  the  back  of  the  hand. 


348  PRACTICAL   ANATOMY. 


CLASSIFICATION  OF  MUSCLES  ACCORDING  TO  FUNCTION. 

(    i.  Extensor  longus  pollicis  ;  insertion,  base  of  second  phalanx. 
Extensors  of  the  pollux   \    2.  Extensor  brevis  pollicis;  insertion,  base  of  first  phalanx. 

I  3.  Extensor  ossis  metacarpi  pollicis;  insertion,  base  of  metacarpal. 

I    i.  Extensor  carpi  radialis  longior  ;   insertion,  base  of  second  meta- 

Ex  tensors  of  the  carfius  -:         ,-  '    •      •      j  •  i  •   u       •       •          •       L         r  i.  •  j 

)    2.  Extensor  carpi  radialis  brevior;  insertion, baseof  third  metacarpal. 

v  3.  Extensor  carpi  ulnaris;  insertion,  base  of  fifth  metacarpal. 

/    i.  Extensor  communis  digitorum ;   insertion,  base  of  second  and 

extensors  of  t  e    tgt  s     -<    2    j£xtensor  minnni  digiti ;  insertion,  with  extensor  communis. 
l.  3.  Extensor  indicis  digiti ;  insertion,  with  extensor  communis. 

Extensors  of  the  forear,,.  \    ['  The  triceps  ;  insertion,  into  the  olecranon  process  of  the  ulna. 
(  2.  The  anconeus ;  insertion  into  the  oblique  line  of  ulna. 

f   i.  Brachio-radialis  ;  insertion,  base  of  styloid  of  radius. 

Supinator  of  the  radius   -,    2.  Supinator  radii  brevis  ;  insertion,  posterior  and  external  surfaces 
(.  of  radius. 

Dissection. — Trace  out  the  tendons  of  the  three  extensors  of  the  thumb  by 
cutting  through  the  deep  digital  fascia.  Take  each  to  its  insertion  according  to 
insertions  given  in  the  classification  above.  Do  not  cut  the  annular  ligament. 
See  if  two  compartments  in  the  annular  ligament  transmit  the  three  thumb 
extensors. 

Extensor  Carpi  Radialis  Longior  and  Brevior. — Locate  the  insertions  of 
these  tendons,  in  the  bases  of  the  second  and  third  metacarpal  bones  respectively 
on  the  radial  side.  Trace  the  same  upward,  under  the  annular  ligament,  and 
behind  the  three  extensors  of  the  thumb.  (Fig.  243.) 

The  extensor  communis  digitorum  sends  a  tendon  to  each  finger.  The 
tendon  of  the  extensor  communis  digitorum  to  the  index  finger  is  joined  by  the 
tendon  of  the  extensor  indicis;  the  tendon  to  the  little  finger,  by  the  tendon  of 
the  extensor  minimi  digiti.  Demonstrate  this  on  your  dissection. 

The  insertion  of  the  extensor  tendons  is  as  follows  (Fig.  243)  :  The  extensor 
tendon  of  each  finger  divides  into  three  parts,  opposite  the  first  phalangeal  articu- 
lation (Fig.  244)  ;  the  middle  portion  is  inserted,  just  across  the  joint,  into  the 
base  of  the  second  phalanx  ;  the  two  lateral  portions  pass  the  joint,  unite  on  the 
dorsum  of  the  second  phalanx,  and  pass  to  the  base  of  the  third  phalanx,  where 
they  are  inserted.  See  whether  this  muscle  and  the  extensor  indicis  occupy  the 
same  compartment  under  the  annular  ligament.  Now  trace  the  extensor  minimi 
digiti  through  a  separate  compartment  in  the  annular  ligament.  (Fig.  244.) 

Insertion  of  the  extensor  carpi  ulnaris  :  Cut  down  on  its  tendon  near  the  base 
of  the  fifth  metacarpal  ;  follow  the  tendon  through  a  groove  behind  the  styloid 
process  of  the  ulna,  and  trace  it  through  a  separate  compartment  in  the  posterior 
annular  ligament. 

Compartments  of  the  Posterior  Annular  Ligament  (Fig.  244). — Cut 
through  the  annular  ligament  and  find  the  following  compartments  and  then- 
contents,  and  see  whether  the  same  are  lined  by  synovial  membrane. 

1.  For  extensor  ossis  metacarpi  pollicis  and  extensor  brevis  pollicis. 

2.  For  extensor  carpi  radialis  longior  and  brevior. 

3.  For  extensor  longus  pollicis. 

4.  For  extensor  communis  digitorum  and  extensor  indicis. 

5.  For  the  extensor  minimi  digiti. 

6.  For  the  extensor  carpi  ulnaris. 

The  Brachio-radialis,  or  Supinator  Radii  Longus. — Supinate  the  radius 
and  you  will  find  this  muscle,  on  the  radial  side,  inserted  into  the-  base  of  the 
styloid  process  of  the  radius.  (Fig.  246.) 


SHOULDER,  ARM,  FOREARM,  HAND.— POSTERIOR  PART.     349 


Trace  to  their  origins  the  radial  group  of  muscles  : 

i .   Supinator  longus,  to  upper  two-thirds  of  external  condylar  ridge  of  the 
humerus.      (Fig.  246.) 


Biceps 

Brachialis  anticus 
Brachio-radialis 


.Extensor  carpi  radialis  lougior 


Extensor  communis  digitorum  


Extensor  carpi  radialis  brevior 


Extensor  ossis  metaearpi  pollicis 


Extensor  brevis  polhcid 


Extensor  longus  pollicis 


Triceps 


Flexor  carpi  ulnaris 


Extensor  carpi  ulnaria 


Extensor  minimi  digiti 


ULNA 


FIG.  243. — MUSCLES  OF  THE  RADIAL  SIDE  AND  THE  BACK  OF  THE  FOREARM. 

2.  Extensor  carpi  radialis  longior,  trace  to  the  lower  one-third  of  external 
condylar  ridge  of  the  humerus. 

3.  Extensor  carpi  radialis  brevior,  to  the  outer  condyle  of  the  humerus. 

To  do  this  properly,  begin  with  the  tendon  and  follow  it  upward,  dividing  the 


PRACTICAL   ANATOMY. 


connective  tissue  between  the  muscle  and  the  ones  on  each  side  of  it.  Be  careful, 
in  doing  this,  not  to  destroy  the  vessels  and  nerves  ;  these  structures  will  become 
numerous  in  the  region  of  the  elbow.  Trace  these  adjacent  muscles  also  up  to 


their  origin. 


Extensor  oasis  metacarpi 
pollicis 


Extensor  carpi  ulnaris 


Extensor  communis  digitorum 


Extensor  minimi  digit! 


Extensor  indicia 


Attachment  of  extensor 
oommunis  digitorum 
to  second  phalanx 


Attachment  of  extensor 
communis  digitorum 
to  third  phalanx 


FIG.  244. — TENDONS  UPON  THE  DOKSIM  01    THE  HAND. 

Trace  the  superficial  group  to  origin  as  follows  (Fig.  243) : 

1.  Extensor  communis  digitorum  to  the  outer  condyle  of  the  humerus. 

2.  Kxtensor  minimi  digiti  to  the  outer  condyle  of  the  humerus. 

3.  Kxtensor  carpi  ulnaris  to  the  outer  condyle  of  the  humerus. 

Notice    the    triple    origin   of  the-   extensor  carpi  ulnaris:  (i)  The  outer  con- 


SHOULDER,  ARM,  FOREARM,  HAND.— POSTERIOR  PART.     351 

dyle  ;  (2)  the  posterior  surface  of  the  ulna  ;  (3)  posterior  border  of  the  ulna,  in 
common  with  the  flexor  carpi  ulnaris.  Dissection  of  this  latter  muscle  requires 
care. 

The  deep  group  of  muscles  and  their  origin  (Figs.  245  and  246)  : 
i.   The  extensor  longus  pollicis — ulna  and  interosseous  membrane. 


Supinator  brevis 


Extensor  oasis  metacarpi  pollicis  — 


Extensor  brevis  pollicis 
Extensor  longus  pollicis 


Radial  extensors 


Flexor  carpi  uliiaris 


Flexor  profundus  digitoru 


Extensor  indicia 


Extensor  oarpi  ulnaria 


FIG.  245. — THE  DEEP  LAYER  OF  THE  BACK  OF  THE  FOREARM. 


2.  The  extensor  brevis  pollicis — radius  and  interosseous  membrane. 

3.  The  extensor  ossis  metacarpi  pollicis — radius  interosseous  membrane  and 
ulna. 

4.  The  extensor  indicis  from  the  ulna. 

In  view  of  the  special  importance  of  the  three  extensors  of  the  thumb  and  the 


352 


PRACTICAL  ANATOMY. 


index   finger,  it  is  necessary  for  the  student  to  trace  each    muscle  to  its  specific 
origin  and  insertion  according  to  the  following  scheme  for  aiding  the  memory  : 

The  extensor  indicis  (Fig.  245')  arises  practically  from  the  posterior  surface 
of  the  lower  one-third  of  the  ulna  and  interosseous  membrane.  Demonstrate  on 
the  cadaver  the  amount  of  ulnar  surface  in  the  lower  third  of  the  bone  which 


Triceps 


Lower  limit  of  orbicular  ligament 


Grooves  for  extensor  ossis,  and  extensor 
primi  internodii  pollicis 

For  extensor  carpi  radialis  longior 

and  brevior 
Extensor  secundi  interuodii  pollicis 


Extensor  primi  interuodii  pollicis 


SUBCUTANEOUS  SURFACE 


Extensor  ossis  metacarpi  pollicis 


AN  APONEUROSIS  IS  ATTACHED  TO  THIS  BORDER 
FROM  WHICH  THE  flexor  AND  extensor 
carpi  vliaris,  AND  flexor  profundus 
digitorum  ARISE 

Extensor  sccundi  internodii  pollicis 


ULNA 
Extensor  indicis 


Extensor  minimi 
Extensor  carpi  ulnaris 


Internal  lateral  ligament 


Extensor  communis  digitorum       Posterior         Posterior  radio-ulnar  ligament 
and  extensor  indicis  radio-carpal 

ligament 

FIG.  246. — THE  LEFT  ULNA  AND  RADIUS.     (Postero-external  view.) 


does  not  give  origin   to   this   muscle.     Observe,  too,   the   septal   origin  of  the 
muscle,  between  this  and  the  extensor  longus  pollicis. 

Now  consider  the  origins  of  the  three'  extensors  of  the  thumb  in  reference  to  : 
(i)  The  posterior  surface  of  the  radius  ;  (2)  the  posterior  surface  of  the  ulna  ; 
(3)  the  posterior  surface  of  the  interosseous  membrane.  Notice,  too,  you  have 
to  deal  with  a  long  hone,  the  ulna  ;  a  short  bone,  the  radius  ;  and  an  interosseous 


SHOULDER,  ARM,  FOREARM,  HAND.— POSTERIOR  PART.     353 


membrane  associated  with  both   bones.      For  purposes  of  convenience  call   the 
extensor  ossis  metacarpi  pollicis  the  strong  muscle.     Then  say  : 

1.  The  long  muscle  (the  extensor  longus  pollicis)  arises  from  the  posterior 
surface  of  the  long  bone  (the  ulna)  and  the  interosseous  membrane. 

2.  The   short  muscle  (the  extensor  brevis   pollicis)  arises  from  the  posterior 


Articular  branch  of  superior 
projundu 

Braehialis  anticus 
Supinator  longus,  cut 


Common  extensor  tendon 


Extensor  carpi  radialis  longior 
and  brevior 


Supinator  brevis 


Posterior  inlerosseous  artery 


Extensor  osais  metacarpi  pollicis 
Supiuator  longus,  cut 

Extensor  primi  iuternodii  polUcis 


Posterior  annular  ligament 

Extensor  carpi  radialis  longior 

Radial  artery 

Dorsal  is  pollicis  artery 

Extensor  secundi  internodii 

pollicis 

First  dorsal  interosseous  muscle 

Dorsalis  indicis  artery 

Pnnceps  pollicis  artery 


Dorsal  digital  artery 


Triceps 

Rete  over  olecranon 
Inlerosseous  recurrent  artery 

Ancoueus,  cut 


Extensor  carpi  ulnaris 
Flexor  carpi  ulnaris 

Origin  of  extensor  secundi  and 
indicator 

Posterior  branch  of  anterior  inlerosseous 

artery 
Interosseous  membrane 


Posterior  ulnar  carpal  artery 
Extensor  carpi  radialis  brevior 
Posterior  radial  carpal  artery 

Third  dorsal  interosseous  artery 
Second  dorsal  inlerosseous  artery 
Melacarpal  or  first  dorsal  interosseous 
artery 


\J 


Vt_>' 


FIG.  247. — THE  BACK  OF  THE  FOREARM,  WITH  THE  POSTERIOR  INTEROSSEOUS  ARTERY  AND 

BRANCHES  OF  THE  RADIAL  AT  THE  BACK  OF  THE  WRIST. 

(From  a  dissection  in  the  Hunterian  Museum.) 

surface  of  the  short  bone  (the  radius)  and  the  interosseous  membrane.      Insertion 
into  the  base  of  the  first  phalanx. 

3.  The  strong  muscle  (the  extensor  ossis  metacarpi  pollicis)  arises  from  the 
posterior  surfaces  of  both  the  long  and  short  bones  (ulna  and  radius)  and  the 
interosseous  membrane.  Insertion  into  base  of  metacarpal  bone. 


354 


PRACTICAL  ANATOMY. 


Observe  that  the  collective  origin  of  the  three  thumb  extensors  practically 
occupies  the  middle  posterior  third  of  ulna,  radius,  and  interosseous  membrane. 
Compare  the  origins  of  these  muscles  as  you  find  them  on  the  cadaver,  with  the 
origins  as  indicated  in  figure  246. 

Now  locate  ( i)  the  posterior  interosseous  artery.  (Fig.  247.)  It  lies  between 
the  superficial  and  deep  groups  of  muscles.  It  is  a  branch  of  the  common  inter- 
osseous branch  of  the  ulnar.  Find  the  space  between  the  oblique  ligament  and 
the  interosseous  membrane,  where  this  vessel  appears.  Also  find  where  it  anasto- 
moses with  the  anterior  interosseous  artery  below.  Notice  that  in  its  course  this 
artery  crosses  the  deep  group  of  muscles,  and  is  attended  in  a  part  of  its  course 
only  by  the  posterior  interosseous  nerve.  Trace  branches  from  this  artery  to  all 
the  muscles  in  this  locality.  This  artery  is  attended  by  the  posterior  interosseous 
nerve  in  the  upper  part  of  its  course.  Show  the  exact  relation  of  artery  and  nerve- 
on  your  work.  (2)  Locate  the  radial  artery  in  the  pulse  region  of  the  wrist.  You 


FIG.  248. — THE  DORSAL  INTEROSSEI. 


will  find  it  passing  under  the  three  extensor  muscles  of  the  thumb,  where  it 
pierces  the  first  interosseous  muscle  and  disappears  into  the  deep  palm. 

The  Dorsal  Interosseous  Muscles  (Figs.  247  and  248). — Study  the  muscles 
and  their  blood-supply.  Find  four  of  these  muscles.  Notice  that  they  arise  by 
two  Heads  from  the  contiguous  surfaces  of  the  metacarpal  bones.  Trace  their 
tendons  of  insertion  to  the  tendon  of  the  extensor  communis  digitorum.  These 
muscles  (Fig.  248), — as  you  might  infer  from  their  insertion, — acting  alone,  are 
abductors  of  the  fingers.  Acting  with  the  palmar  interossei  and  lumbricales, 
they  produce  flexion  at  the  metacarpo-phalangeal  and  extension  at  the  phalan- 
geal  articulations.  Acting  in  this  way,  they  place  the  fingers  in  position  for  hold- 
ing the  pen.  These  muscles  arc  all  supplied  by  the  ulnar  nerve. 

The  Supinator  Radii  Brevis. — Detach  all  the  muscles  that  arise  from  the 
outer  comlylc  :  The  extensor  carpi  radialis  brevior,  the  extensor  communis 
digitorum,  the  extensor  minimi  digiti.  and  the  extensor  carpi  ulnaris.  Do  this 


SHOULDER,  ARM,  FOREARM,  HAND.— POSTERIOR  PART.     355 

in  such  a  way  as  not  to  injure  the  nerve-supply  from  the  musculo-spiral. 
Now  pull  these  muscles  slightly  aside  and  see  the  supinator  brevis.  (Fig.  247.) 
Trace  it  to  the  following  origins  and  insertions  : 

Origins. — (i)  Lower  and  back  part  of  external  condyle  ;  (2)  the  external  lateral 
ligament  of  the  elbow-joint;  (3)  the  orbicular  ligament;  (4)  the  triangular 
depression  below  the  lesser  sigmoid  cavity  of  the  ulna,  especially  along  its  pos- 
terior margin,  which  forms  the  upper  part  of  the  external  border  of  the  ulna. 

Insertion. — (i)  The  back  of  the  neck  of  the  radius;  (2)  the  anterior  and 
outer  surfaces  of  the  radius  above  and  at  the  upper  border  of  the  oblique  line. 

You  will  now  find  the  posterior  interosseous  nerve  issuing  from  the  lower 
border  of  the  muscle.  This  nerve  supplies  all  the  muscles  in  this  region  except 
the  radial  group,  which  were  supplied  by  the  musculo-spiral,  before  this  nerve 
divided  into  the  radial  and  posterior  interosseous.  The  radial  nerve  is  a  branch 
of  the  musculo-spiral. 

The  radial  nerve  perforates  the  deep  fascia,  between  the  extensor  carpi 
radialis  and  supinator  longus  about  three  inches  above  the  carpus.  Find  where 
the  nerve  comes  through  the  deep  fascia  and  trace  the  same  to  the  dorsum  of 
the  hand,  and  to  three  and  one-half  fingers. 

The  anconeus  (Fig.  245)  arises  from  the  back  part  of  the  outer  condyle. 
It  is  inserted  into  the  olecranon  and  posterior  surface  of  the  ulna.  Remove  this 
muscle  from  its  attachment,  turn  the  same  aside,  and  see  the  orbicular  ligament 
of  the  radius  and  the  elbow-joint.  Cut  through  the  orbicular  ligament  and 
dislocate  the  head  of  the  radius. 

The  region  of  the  shoulder  (Fig.  249)  shows  : 

1.  The  deltoid  muscle  and  its  nerve-supply,  the  circumflex. 

2.  The  supraspinatus  muscle  (Fig.  251)  under  the  trapezius.      (Fig.  250.) 

3.  The  infraspinatus  muscle  under  the  deltoid  aponeurosis. 

4.  The  teres  minor  muscle,  from  the  axillary  border  of  scapula. 

5.  The  triceps  muscle  and  its  three  heads. 

6.  The  teres  major  muscle,  with  the  latissimus  dorsi. 

7.  The  triangular  space  and  the  dorsalis  scapulae  artery. 

8.  The  quadrangular  space  and  its  circumflex  structures. 

9.  The  circumflex  nerve  and  vessels  in  the  quadrangular  space. 

0 O.  The  anterior  and  posterior  circumflex  arteries  and  veins. 

1 1.  The  musculo-spiral  nerve  and  the  superior  profunda  artery. 

12.  The  scapular  head  of  tJie  triceps  muscle  between  the  tereals. 

The  circumflex  quadrangular  space  (Fig.  249)  is  bounded  :  (i)  Externally  by 
the  surgical  neck  of  the  humerus  ;  (2)  internally  by  the  long  or  scapular  head 
of  the  triceps  ;  (3)  superiorly  by  the  teres  minor  ;  (4)  inferiorly  by  the  latissimus 
dorsi  and  teres  major  muscles  ;  (5)  contents  :  posterior  circumflex  artery,  a 
branch  of  the  axillary,  and  the  circumflex  nerve,  from  the  posterior  cord  of  the 
brachial  plexus. 

The  triangular  space  (Fig.  249)  is  bounded  :  (i)  Externally  by  the  scapular 
head  of  the  triceps  ;  (2)  superiorly  by  the  teres  minor  ;  (3)  inferiorly  by  the  teres 
major  and  latissimus  dorsi ;  (4)  contents  (Fig.  249)  :  arteria  dorsalis  scapulae,  a 
branch  of  the  subscapular  artery. 

A  second  triangular  space  is  bounded  (Fig.  249):  (i)  Externally  by  the 
humerus  and  outer  humeral  head  of  triceps  ;  (2)  internally  by  the  scapular  head 
of  the  triceps  ;  (3)  superiorly  by  the  teres  major  and  latissimus  dorsi  ;  (4)  it 
contains  the  musculo-spiral  nerve,  from  the  posterior  cord  of  the  brachial  plexus, 
and  the  superior  profunda  artery,  a  branch  of  the  brachial  ;  (5)  it  transmits  the 
external  cutaneous  branch  of  musculo-spiral  nerve. 

Dissection. — The  Deltoid  Muscle  (Fig.  250). — Develop  the  posterior  border 
of  this  muscle  by  cutting  freely  with  the  scissors  the  deltoid  aponeurosis  between 


356 


PR  A  CTJCA  L  AN  A  TOM  \ '. 


this  muscle  and  the  triceps,  teres  minor,  infraspinatus,  and  trapezius  below. 
Now,  with  a  sharp  scalpel  cut  the  scapular  origin  of  the  deltoid,  along  the  whole 
length  of  the  inferior  border  of  the  spine  and  acromion  process  of  the  scapula. 
(Fig.  249.)  Turn  the  muscle  forward  and  see,  in  a  mass  of  connective  tissue 
and  fat,  the  posterior  circumflex  artery  and  circumflex  nerve  emerging  from  the 
quadrangular  space.  (Fig.  249.)  Trace  the  circumflex  nerve  to  the  deltoid  and 
teres  minor  muscles.  Trace  the  deltoid  to  its  insertion  into  the  deltoid  depres- 
sion on  the  outer  surface  of  the  humerus,  middle  one-third.  Take  note  of  the 
triangular  shape  of  a  number  of  muscles  about  the  shoulder. 

The  Teres  Major  and  Latissimus  Dorsi   (Figs.   250-253). — Divide   the 
connective  tissue  between  these  two  muscles.      Trace  them   under  the  scapular 


Infra-spinatus,  cut 
ACROMIAL  PROCESS 

Suprascapular  artery 
SPINE  OF  SCAPULA 


Teres  minor 

Superior  profunda  artery 

Posterior  circumflex  artery 
I  Deltoid,  reflected 


Infra-spinatus,  cut 

Teres  major 
Dorsal  scapular  artery 

Branch  of  dorsal  scapular  arferi/ 

'\l-:it\'E  TO  TERES  MINOR 


'SCI  Y,  O-SPIRA  L  NER  VE 
Outer  head  of  triceps 

EXTERN. \  I.  (TT.i  NEO US 
BKAM'II  <,!•• 
MUSCULO- 

xriU.il.  NERVE 


Lone  head  of  triceps 
CUTANEOUS  BRANCH  OF  CIRCUMFLEX  NERVE,    (  IT 


FIG.  249. — THE  POSTERIOR  CIRCUMFLEX  ARTERY. 
(From  a  dissection  by  Mr.  Horner  in  the  Museum  of  St.  Bartholomew's  Hospital.) 


head  of  the  triceps  to  the  humerus.  These  muscles  form  the  lower  bourn 
of  both  the  quadrangular  and  triangular  spaces.  They  are  inserted  as  follous  : 
The  latissimus  dorsi  into  the  bottom  of  the  bicipital  groove  as  high  as  the  lesser 
tuberosity  of  the  humerus  ;  the  teres  major  into  the  inner  lip  of  the  bicipital 
groove  for  two  inches  in  length.  Note  that  both  these  tendons  are  inclosed  in  a 
rather  tough  sheath  of  connective  tissue. 

The  teres  minor  (Figs.  251  and  253)  is  separated  near  the  humerus  from 
the  teivs  major  by  the  scapular  head  of  the  triceps.  Divide  the  connective 
tissue  between  the  teres  minor  and  the  infraspinatus  above  and  the  teres  major 
below.  (Fig.  250.)  The  teres  minor  arises  from  the  axillary  border  of  the 
scapula.  It  is  synergistic  in  its  action  to  the  deltoid  and  derives  its  nerve-supply 
from  the  same  circumflex  nerve.  It  is  inserted  into  the  lowest  facet  of  the 


SHOULDER,  ARM,  FOREARM,  II AArD.— POSTERIOR  PART.      357 


Triceps 


Teres  minor 
Infraspinatus 

Teres  major 

Rhomboideus  major 

Peotoralis  major 


Oluteus  medius 


Gluteus  maximus 


V\<;.  250. — FIRST  LAYER  OF  THE  MUSCLES  OF  THE  BACK. 


358 


PRACTICAL  ANATOMY. 


greater  tuberosity  of  the  humerus.  (Fig.  253.)  Demonstrate  the  quadrangular 
and  triangular  spaces  according  to  the  outline  given  in  the  preceding  pages. 
(Fig.  251.) 

The  Infraspinatus  (Fig.  251). — Now  cut  this  muscle  at  its  insertion  into 
the  middle  facet  of  the  greater  tuberosity  ;  turn  the  same  backward,  taking  care 
not  to  injure  the  capsule  of  the  shoulder-joint  and  the  vessels  and  nerves  that 
enter  under  the  surface  of  the  muscle.  This  muscle  arises  from  the  outer  two- 
thirds  of  the  infraspinous  fossa.  (Fig.  252.)  It  is  covered  by  a  dense  layer  of 


Supra-spinatua 


Infra-spinatua 
Teres  minor 


Teres  major 


Long  head  of  triceps 


Outer  bead  of  triceps 


Inner  bead  of  triceps 


FIG.  251. — BACK  VIEW  OK  THE  SCAPULAR  MUSCLES  AND  IK 

deep  fascia.      The  muscle  is  triangular  in   shape,  and  derives   its   nerve-supply 
from  the  infraspinous  branch  of  the  suprascapular  nerve. 

The  supraspinatus  muscle  (I  ig.  251)  arises  from  the  outer  two-thirds  of 
the  fossa  of  the  >ame  name  and  also  from  the  dense  aponcurosis  covering  the 
muscle.  It  is  inserted  into  the  upper  facet  «'f  the  greater  tuberosity  of  the 
humerus.  It  is  covered  (i)  by  a  dense  fascia  of  the  same  name  ;  (2)  by  the 
trape/.ius  muscle,  which  is  inserted  into  the  upper  lip  of  the  scapular  spine.  (Fig. 
250.)  Kxpose  this  supraspinatus  muscle  by  cutting  the  insertion  of  the  trape/ius. 
Then  you  may  trace  the  supraspinatus  under  the  acromion  process  to  its  inser- 


SHOULDER,  ARM,  FOREARM,  HAND.— POSTERIOR  PART.      359 

tion.  Cut  this  muscle  at  its  insertion,  turn  it  back  (Fig.  254),  and  find  the 
vessels  and  nerves — the  suprascapular — that  supply  this  region. 

The  suprascapular  artery  and  nerve  will  come  into  view  as  you  turn  aside 
the  supraspinatus  muscle.  (Figs.  249—254.)  The  nerve  you  will  trace  through 
the  suprascapular  foramen  under  the  transverse  ligament.  (Fig.  252.)  The  artery 
crosses  the  transverse  ligament.  (Fig.  252.)  Each  structure  divides  into  supra- 
spinous  and  infraspinous  branches.  Trace  these  vessels  and  nerves  out  to  their 
respective  localities  of  distribution.  (Fig.  254.) 

The  anastomosis  between  the  suprascapular  artery  and  the  dorsal  branch  of 
the  subscapular  takes  place  in  the  infraspinous  fossa,  on  the  bone.  Find  this. 
(Fig.  249.)  Anastomosis  about  the  shoulder  includes  the  following  arteries, 
which  you  may  now  demonstrate.  (Fig.  254) :  Circumflex,  subscapular,  dorsalis 

Transverse  ligament 


Conoid  ligament 


Acromio-clavicular 
ligament 


Tendon  of  infra- 
spinatus  and  tares 
minor 

Inferior  transverse 
or  spino-glenoid 
ligament 
Capsule  of  shoulder 


FIG.  252. — POSTERIOR  VIEW  OF  THE  SHOULDER-JOINT,  SHOWING  ALSO  THE  ACROMIO- 
CLAVICULAR  JOINT  AND  THE  PROPER  LIGAMENTS  OK  THE  SCAPULA. 


scapulae,  suprascapular,  posterior  scapular  artery,  a  continuation  of  the  trans- 
versalis  colli,  a  branch  of  the  thyroid  axis  of  the  subclavian. 

The  triceps  muscle  (Fig.  253)  has  three  heads.  The  longer  scapular 
head  you  will  now  very  carefully  trace  to  the  axillary  border  of  the  scapula, 
immediately  below  the  glenoid  fossa.  As  you  have  already  observed,  this  head 
assists  in  forming  boundaries  for  the  quadrangular  space  and  also  for  the  two 
triangular  spaces.  The  whole  posterior  surface  of  the  humerus  is  occupied  by 
the  inner  and  outer  heads  of  the  triceps  muscle,  and  the  musculo-spiral  groove. 

Dissection. — Locate  the  musculo-spiral  nerve  and  the  superior  profuncla 
artery  in  the  second  triangle.  (Fig.  249.)  Now  the  nerve  will  pass  between  the 
bone  and  muscle.  Cut  the  muscle  in  a  line  corresponding  to  the  course  of  the 
nerve,  until  you  come  to  a  point  two  inches  above  the  outer  condyle.  The  mus- 
cular mass  attached  to  the  posterior  surface  of  the  humerus  above  the  groove,  in 


36° 


PR  A  CTICAL  ANA  TOM  3 . 


which  you  now  see  the  musculo-spiral  nerve,  is  called  the  external,  or  long 
humeral  head  of  the  triceps  ;  the  mass  below  the  musculo-spiral  groove  is  called 
the  internal  or  short  humeral  head.  Trace  the  triceps  muscle  to  its  insertion, 
into  the  olecranon  process  of  the  ulna.  Cut  the  insertion  of  the  triceps  and 
study  the  capsule  of  the  elbow-joint  and  the  olecranon  fossa. 


FIG.  253. — TRICEPS  BRACHIALIS,  POSTERIOR  A.SI>KCT. 

I.  Long,  middle,  or  scapular  head.  2.  Its  tendon  of  origin  from  scapula.  3.  External,  or  long  humeral 
head.  4.  Internal,  or  short  humeral  head.  5.  Common  tendon.  6.  Attachment  to  olecranon. 
7.  Anconeus.  8,  8.  Upper  portion  of  deltoid,  posterior  half  removed.  9.  Lower  portion. 
10.  Supraspinatus.  II.  Infraspinatus.  12.  Teres  minor,  middle  portion  removed.  13.  Insertion 
of  teres  minor  into  humerus.  14.  Teres  major.  15.  Upper  extremity  of  latissimus  dorsi.  16.  Supi- 
nator  longus.  17.  Extensor  carpi  radialis  longior.  18.  Extensor  carpi  ulnaris.  19.  Flexor  ca: 
ulnaris. 


* 


Nei~i>e-supply  to  the  Triceps. — As  you  dissect  between  the  two  humeral  heads 
of  the  triceps,  notice  the  large  number  of  branches  given  off  to  the  muscle  from 
the  musculo-spiral  nerve,  a  branch  of  the  posterior  cord  of  the  brachial  plexus. 


1.  J /<>:,'  many  origins  /ins  tin  deltoid  muscle  / 

Two  ;  one  from  the  lower  lip  of  the  scapular  spine  and  acromion,  another  from 
the  outer  one-third  of  the  clavicle.     (Fig.  252.) 

2.  Tlie  origin  of  (lie  deltoid,  tlicn,  may  be  said  to  correspond  to  tlie  insertion  oj 
muscle  f 

To  the  insertion  of  the  trape/itis,  since  this  muscle  is  inserted  into  the  uppei 


SHOULDER,  ARM,  FOREARM,  HAND.— POSTERIOR  PART.     361 

lip  of  the  scapular  spine  and  acromion,  and  into  the  posterior  outer  one-third 
of  the  clavicle.  (Fig.  252.) 

3.   Describe  the  circumflex  nerrc. 

It  is  a  branch  of  the  posterior  cord  of  the  brachial  plexus.  (Fig.  42.)  It 
passes  through  the  circumflex  quadrangular  space,  to  the  back  of  the  shoulder. 
It  gives  muscular  branches  to  the  deltoid  and  teres  minor  muscles,  and  cutaneous 
branches  to  the  skin  covering  the  insertion  of  these  muscles  and  articular 
branches  to  the  shoulder-joint.  (Hilton's  la\v.) 


Supra-spinatua     Suprasca/mlar  artery 

Posterior  scapular  artery  |       |  Infra-spinatus 

Hhomboideus  minor          / 


Levator  anguli  scapulae 


Triceps,  cut 


Deltoid,  insertion 
Deltoid 


Trapezius 
Rhomboideus  major 

Terea  major  muscles 


Deltoid  muscle 
/ 
Triceps 


Teres  major,  insertion 
Dorsalis  scapulae  artery   Posterior  circumflex  artery 

•  FIG.  254. — THE  DORSAL  SCAPULAR  ARTERY. 
(From  a  dissection  in  the  Museum  of  the  Royal  College  of  Surgeons.) 


4.  Describe  the  suprascapular  nerve. 

A  branch  of  the  upper  trunk  of  the  brachial  plexus.  (Fig.  42.)  It  passes 
through  the  constant  suprascapular  foramen.  It  gives  muscular  branches  to 
(i)  the  supraspinatus,  (2)  the  infraspinatus,  and  articular  branches  from  each 
muscular  branch,  to  the  shoulder-joint.  (Hilton's  law.) 

5.  Describe  the  muscnlo-spiral  nerve. 

It  is  a  branch  of  the  posterior  cord  of  the  brachial  plexus.  (Fig.  42.)  It 
may  be  found  on  the  floor  of  the  second  triangular  space.  (Fig.  249.)  It  passes 
between  the  two  humeral  heads  of  the  triceps  in  the  musculo-spiral  groove  of  the 
humerus.  It  lies  between  the  brachialis  anticus  and  brachio-radialis  muscles  in  the 
lower  third  of  the  arm.  It  gives  muscular  branches  to  the  triceps  and  anconeus 
24 


362  PRACTICAL  ANATOMY. 

and  to  all  the  muscles  in  the  radial  region,  and  also  to  all  the  muscles  on  the  pos- 
terior part  of  the  foramen.  Its  cutaneous  branches  are  as  follows  :  (i)  Radial,  to 
the  integument  of  the  ball  of  the  thumb  and  to  three  and  one-half  ringers  dorsally, 
as  far  as  the  base  of  the  distal  phalanx  (Fig.  242) ;  (2)  internal  cutaneous  branches 
to  the  skin  on  the  inner  and  posterior  part  of  the  arm  ;  (3)  external  cutaneous 
branches  to  the  skin  on  the  outer  and  front  part  of  the  arm.  (Fig.  241.)  The 
articular  branch  to  the  shoulder  is  sometimes  taken  with  the  circumflex.  The 
posterior  nerve-cord  is  composed  of  both  the  circumflex  and  musculo-spiral  and 
other  branches. 

6.  Name  tJic  muscles  arising  from  the  external  condylar  ridge. 
The  brachio-radialis  and  extensor  carpi  radialis  longior. 

7.  Give  the  origin,  course,  and  distribution  of  the  posterior  interosseons  nerve. 
A  branch  of  the  musculo-spiral ;  it  passes  between  the  upper  and  deep  layers 

of  the  supinator  brevis  muscle.  It  lies  between  the  deep  and  superficial  groups 
of  posterior  forearm  muscles,  which  it  supplies.  Note  that  the  musculo-spiral 
nerve  gives  off  branches  to  the  radial  group  of  muscles  prior  to  its  division  into 
the  radial  and  posterior  interosseous.  Demonstrate  this  on  your  dissection. 

If  you  have  not  already  done  so,  review  you  dissection  of  the  musculo- 
spiral  nerve  and  show  that  the  branches  that  supply  the  humeral  heads  of  the 
triceps  muscle  are  given  off  at  the  back  of  the  humerus  ;  that  branches  are  given 
off  in  the  axilla  to  the  scapular  head.  This  nerve  sometimes  accompanies  the 
ulnar  nerve  as  a  long  slim  branch,  known  as  the  ulnar  collateral. 

8.  Describe  tlie  dorsal  inter ossei  muscles. 

They  are  four  in  number.  They  are  supplied  by  the  ulnar  nerve.  They 
have  origin  from  the  contiguous  sides  of  the  metacarpal  bones.  (Fig.  248.) 
Their  single  independent  action  is  abduction  of  the  fingers,  which  is  always 
associated  physiologically  with  supination  of  the  radius.  Their  synergistic  action 
is  with  the  palmar  interossei  and  lumbricales  to  produce  metacarpo-phalangeal 
flexion,  and  extension  of  the  second  and  third  phalanges.  They  are  inserted 
into  the  bases  of  three  fingers,  as  shown  in  figure  248. 

1.  Describe  tJie  median  nerve. 

It  arises  by  two  heads — an  outer  and  an  inner — from  the  outer  and  inner 
cords  of  the  brachial  plexus  respectively.  (Fig.  42.)  It  accompanies  the  axillary 
artery  and  its  prolongation,  the  brachial,  to  the  elbow.  It  gets  into  the  forearm 
by  passing  between  the  condylar  and  coronoid  heads  of  the  pronator  radii  tores 
muscle.  It  gives  off  no  branches  to  the  flexor  muscles  of  the  forearm.  It  is,  in 
rare  cases,  fused  with  the  musculo-cutaneous  nerve.  It  is  said  to  give  off  two 
articular  branches  to  the  elbow-joint.  It  supplies  all  the  muscles  on  the  anterior 
surface  of  the  forearm,  except  the  flexor  carpi  ulnaris,  and  one-half  of  the  flexor 
profundus  digitorum.  It  supplies  three  and  one-half  fingers  with  sensation. 
In  the  hand  it  supplies  the  two  radial  lumbricales  and  all  the  muscles  of  the 
thenar  eminence,  except  the  adductor  pollicis  and  one  head  of  the  flexor  brevis 
pollicis.  It  is  accompanied  by  an  artery  below  the  elbow.  Sometimes  this  artery 
is  as  large  as  the  radial.  It  passes  under  the  anterior  annular  ligament.  In  the 
forearm  the  median  nerve  lies  in  the  sheath  of  the  flexor  sublimis  digitorum,  on 
the  posterior  surface  of  this  muscle.  The  digital  branches  of  this  nerve  supply 
the  finger-joints. 

2.  Describe  tlic  itlnar  nerrc. 

It  is  a  branch  of  the  inner  cord  of  the  brachial  plexus.  It  is  attended  by  the 
inferior  profunda  artery  above  the  elbow,  and  by  the  ulnar  below.  It  gains  the 
forearm  by  passing  between  the  two  heads — olecranon  and  condylar — of  the 
flexor  carpi  ulnaris.  It  supplies  the  flexor  carpi  ulnaris,  and  the  ulnar  half  of 
the  flexor  profundus  digitorum.  It  supplies  one  and  one-half  fingers  dorsally 
and  paltnarly.  It  supplies  in  the  hand  all  the  muscles  not  innervated  by  the 


SHOULDER,  ARM,  FOREARM,  HAND.— POSTERIOR  PART.     363 

median  nerve.  It  gives  articular  branches  to  the  elbow  and  wrist,  and  all  subse- 
quent joints  moved  by  the  muscles  which  it  supplies.  Demonstrate  the  dorsal 
ulnar  cutaneous  nerve.  (Fig.  242.) 

3 .  Describe  the  musculo-spiral  nerve. 

It  is  a  branch  of  the  posterior  cord  of  the  brachial  plexus.  (Fig.  42.)  It  is 
found  between  the  two  humeral  heads  of  the  triceps  muscle  in  the  musculo-spiral 
groove  with  the  superior  profunda  artery.  In  the  lower  one-third  of  the  arm  it 
lies  between  the  brachialis  anticus  and  supinator  longus.  In  this  place  it  gives  off 
branches  to  the  radial  group  of  muscles — the  supinator  radii  longus,  the  exten- 
sor carpi  radialis  longior  and  brevior.  It  divides  then  into  the  radial  and  poste- 
rior interosseous.  The  posterior  interosseous  passes  through  the  supinator 
b  re  vis  and  then  supplies  the  muscles  on  the  posterior  part  of  the  forearm.  The 
radial  branch  becomes  cutaneous  by  piercing  the  deep  fascia  in  the  lower  one- 
third  of  the  forearm,  between  the  supinator  longus  and  the  extensor  carpi 
radialis.  In  the  hand  the  nerve  supplies  the  ball  of  the  thumb  and  adjacent  three 
and  one-half  fingers  dorsally.  (Fig.  242.)  The  musculo-spiral  nerve  gives  off  two 
cutaneous  branches  to  the  skin  over  the  insertion  of  the  triceps  and  anconeus. 

4.  Describe  the  musculo-cutaneous  nerve. 

This  is  a  branch  of  the  outer  cord  of  the  brachial  plexus.  (Fig.  42.)  It  per- 
forates, as  a  rule,  the  coraco-brachial  muscle,  and  gains  the  intermuscular  space 
between  the  biceps  and  brachialis  anticus.  It  supplies  the  coraco-brachial  and  the 
flexor  muscles  of  the  forearm,  the  biceps,  brachialis  anticus,  and  supinator  longus  ; 
the  cutaneous  part  is  distributed  to  the  skin  over  the  insertion  of  these  muscles. 

5.  Describe  the  circumflex  nerve. 

It  is  a  branch  of  the  posterior  cord  of  the  brachial  plexus.  (Fig.  42.)  It  passes 
through  the  quadrangular  space  to  the  back  of  the  shoulder  with  the  posterior 
circumflex  artery.  (Fig.  249.)  It  supplies  the  deltoid  and  teres  minor  muscles. 
It  gives  two  articular  branches  to  the  shoulder-joint  and  cutaneous  branches  to 
the  skin  over  the  insertion  of  the  deltoid  and  teres  minor  muscles. 

6.  Name  the  important  regions  of  geometrical  parts  in  the  upper  extremity. 
(i)  The  radial  groove  ;  (2)  the  ulnar  groove  ;  (3)  the  cubital  fossa;  (4)  the 

brachial  groove  ;  (5)  the  axilla  ;  (6)  the  quadrangular  space  •  (7)  the  first  tri- 
angular space  ;  (8)  the  second  triangular  space. 

7.  Give  t/ic  special  names  for  deep  fascia  in  the  tipper  extremity. 

(i)  Anterior  annular  ligament;  (2)  posterior  annular  ligament ;  (3)  dorsal 
fascia  ;  (4)  palmar  fascia  ;  (5)  ligamenta  vaginales  ;  (6)  bicipital  fascia  ;  (7)  axillary 
fascia;  (8)  clavi-pectoral  fascia;  (9)  costo-coracoid  ligament;  (10)  pectoral  apo- 
neurosis  ;  (11)  deltoid  aponeurosis  ;  (12)  supraspinous  fascia  ;  (13)  infraspinous 
fascia  ;  (14)  superior  transverse  scapular  ligament ;  (i  5)  inferior  transverse  scapu- 
lar ligament.  (Fig.  252.) 

8.  What  structures  did  you  find  under  the  anterior  annular  ligament  at  the 
carpus  ? 

(i)  The  flexor  sublimis  digitorum  ;  (2)  the  flexor  profundus  digitorum  ;  (3) 
the  flexor  longus  pollicis  ;  (4)  the  median  nerve  and  its  artery. 

9.  Give  boundaries  of  the  radial  groove,  and  its  contents. 

On  the  radial  side  is  the  supinator  longus  muscle  ;  on  the  ulnar  side,  in  the 
upper  third,  the  pronator  radii  teres  ;  in  the  remainder  of  its  course,  the  flexor 
carpi  radialis.  In  front  of  the  artery  the  skin  and  fasciae  form  the  roof  of  the 
radial  groove.  Behind  the  artery,  from  above,  are  :  (i)  The  biceps  ;  (2)  supinator 
brevis  ;  (3)  pronator  radii  teres  ;  (4)  flexor  sublimis  digitorum  ;  (5)  flexor  longus 
pollicis  ;  (6)  pronator  quadratus  ;  (7)  a  small  part  of  the  lower  end  of  the  radius. 
The  radial  groove  contains  the  radial  artery  and  its  vena;  comites. 

10.  Give  boundaries  and  contents  of  the  ulnar  groove. 

The  ulnar  groove  contains  the  ulnar  artery  and  its  venae  comites.    The  artery 


364 


PRACTICAL    ANATOMY. 


is  a  branch  of  the  brachial  artery,  being  given  off  from  this  vessel  in  the  cubital 
fossa.  The  groove  is  limited  on  the  ulnar  side  by  the  flexor  carpi  ulnaris,  this 
muscle  being  the  guide  to  the  artery  in  the  lower  two-thirds  of  its  forearm  course  ; 
on  the  radial  side  by  the  flexor  sublimis  digitorum  ;  behind  by  the  brachiali.s 
anticus,  the  flexor  profundus  digitorum,  and  the  pronator  quadratus.  The  ulnar 
artery  is  covered  in  the  lower  two-thirds  by  the  skin  and  fasciae.  In  its  course 
from  the  cubital  fossa  to  the  ulnar  groove  proper,  the  artery  passes  behind  all  the 
muscles  that  originate  from  the  inner  condyle  of  the  hurherus,  except  the  flexor 
carpi  ulnaris.  On  entering  the  groove  proper  the  artery  is  joined  by  the  ulnar 
nerve. 

1 1.    Give  boundaries  of  the  cubital  fossa,  and  tell  what  you  found  in  this  fossa. 

Externally,  is  the  supinator  longus  muscle  ;  internally,  the  pronator  radii  teres  ; 
above,  an  imaginary  line  passing  through  the  humeral  condyles.  The  roof  is 
formed  by  the  skin  and  fasciae.  The  floor  is  formed  by  the  brachialis  anticus  and 
supinator  brevis,  containing  between  its  superficial  layers  the  posterior  inter- 
osseous  nerve.  The  fossa  contains  the  tendon  of  the  biceps  and  bicipital  tuber - 
osity  ;  the  median  nerve  ;  the  brachial  artery,  dividing  into  the  radial  and  ulnar 
arteries  ;  the  musculo-spiral  nerve,  dividing  into  the  radial  and  posterior  inter- 
osseous  nerves  ;  the  cutaneous  branch  of  the  musculo-cutaneous  nerve  ;  the 
median  cephalic  and  median  basilic  veins. 

The  student  should  now  review  the  scheme  of  the  brachial  plexus  on  page 
77,  et  seq. 


POSTERIOR  PART  OF  LOWER  EXTREMITY. 


Dissection. — Locate  greater  trochanter,  sacrum,  coccyx,  tuber  of  ischium, 
crest  of.  ilium,  inner  and'  outer  hamstrings,  head  of  fibula,  neck  of  fibula,  os  calcis, 
inner  and  outer  malleoli. 

Incisions. — (i)  From  centre  of  crest  of  ilium  to  centre  of  the  os  calcis  ;  (2) 
from  greater  trochanter  to  coccyx ;  (3)  from  internal  to  external  condyle  ; 
(4)  from  inner  malleolus  to  outer  malleolus.  Cut  deeply  enough  to  permit  the 
edges  of  the  skin  to  separate  one-half  of  an  inch  with  ease.  In  removing  the 
skin  from  any  area,  cut  closely  enough  that  light  may  shine  through  the  skin. 
The  thing  you  see  now  having  removed  the  skin  is  the  superficial  fascia.  It 
contains  the  following  structures  in  a  variable  amount  of  fat  (Fig.  255) : 

Cutaneous  or  sensory  nerves  in  figure  255. 

1 .  TIic  twelfth  or  last  thoracic  nerve  below  the  twelfth  rib. 

2 .  The  iliac  brancJi  of  the  ilio-liypogastric  nerve. 

3 .  Posterior  branches  of  the  lumbar  and  sacral  nerves. 

4.  The  external  cutaneous  nerve  of  the  lumbar  plexus. 

5.  Tlie  small  sciatic  of  the  sacral  plexus. 

6.  The  cutaneous  branch  of  the  obturator  nerve. 

7.  Twigs  from  the  long  or  internal  saphenous. 

8.  The  short  saphenous,  formed,  as  you  see  in  figure  255,  by  the  communicans 
tibialis   and  communicans  fibularis,  branches   of  internal  and  external  popliteal 
respectively. 

9.  The  short  saphenous  vein,  with  the  nerve  described  in  the  preceding  para- 
graph.     This  vein  comes  from  the  outer  end  of  the  dorsal  arch  of  the  foot,  runs 
behind  the  outer  malleolus   of  the   fibula,  passes  up  the  mid-line  of   the   leg, 
between  the  two  heads   of  the  gastrocnemius  muscle,  pierces  the  deep  popliteal 
fascia,  and  opens  into  the  popliteal  vein. 

Describe  the  twelfth  thoracic  nerve. 

It  is  seen  giving  (i)  a  cutaneous  branch  to  the  anterior  part  of  the  gluteal 
region  ;  (2)  a  cutaneous  branch  to  the  anterior  part  of  the  abdominal  walls  as  low 
as  the  hypogastric  region.  The  nerve  lies  below  the  last  rib,  with  the  first  lumbar 
artery.  It  crosses  the  quadratus  lumborum  muscle,  and  its  muscular  branches 
are  distributed  like  the  other  abdominal  intercostals. 

Describe  the  ilio- hypogastric  nerve. 

This  is  a  branch  of  the  lumbar  plexus,  being  given  off  from  the  first  lumbar 
with  the  ilio-inguinal  nerve.  The  iliac  branch  supplies  the  integument  of  the 
front  part  of  the  gluteal  region.  The  hypogastric  branch  pierces  the  aponeurosis 
of  the  external  oblique  muscle  one  inch  above  the  external  abdominal  ring,  and 
supplies  the  skin  in  this  region. 

Observe  that  the  posterior  branches  of  the  lumbar  and  sacral  nerves  supply 
the  skin  over  the  glutens  maximus  muscle. 

Remember,  the  external  cutaneous  branch  of  the  lumbar  plexus  supplies  the 
skin  covering  the  vastus  externus,  and  may  be  considered  a  dismembered  branch 
of  the  anterior  crural  nerve,  according  to  Hilton's  law. 

365 


366  PRACTICAL   ANATOMY. 

The  small  sciatic  nerve  supplies  the  skin  covering  the  flexor  muscles  of  the 
leg.  It  may  be  regarded  as  the  dismembered  branch  of  the  great  sciatic  nerve. 
The  long  pudendal  branch  of  this  nerve  crosses  the  tuber  ischii  and  is  distributed 
to  the  scrotum  of  the  male  and  its  homologue,  the  labia  majora  of  the  female. 

The  long  saphenons  nerve  is  a  branch  of  the  anterior  crural,  but  to  carry  out 
the  law  governing  cutaneous  distribution,  it  extends  to  the  inner  side  of  the 
ankle,  to  supply  the  skin  over  the  fullest  insertion  (periosteal)  of  the  sartorius. 

If  you  will  now  clean  off  all  the  fat,  you  will  see  a  rather  dense  fascia  cover- 
ing the  muscles.  This  is  the  deep  fascia.  That  part  of  this  fascia  that  covers 
the  popliteal  space  is  called  the  popliteal  fascia.  Now  remove  the  deep  fascia 
and  make  your  muscles  look  like  figure  256,  taking  pains  not  to  destroy  vessels 
and  nerves. 

You  have  now  exposed  to  view  the  gluteus  mediu's  and  maximus,  biceps, 
semitendinosus,  semi-membranosus,  gracilis,  sartorius,  plantaris,  gastrocnemius, 
and  tendo  Achillis. 


THE  POPLITEAL   SPACE 

is  a  surgical  area  occupying  the  lower  posterior  one-third  of  the  thigh  and  the 
upper  posterior  one-sixth  of  the  tibia.  It  is  diamond  in  shape.  Its  floor  is 
formed  by  the  femur,  ligament  of  Winslow,  and  popliteus  muscle.  Its  roof  is 
formed  by  the  skin,  superficial  fascia,  and  deep  popliteal  fascia.  (See  above.)  The 
space  is  bounded  (Fig.  256),  above  the  joint,  externally  by  the  biceps  muscle, 
internally  by  the  semitendinosus,  semi-membranosus,  gracilis,  and  sartorius  ; 
below  the  joint,  externally  by  the  outer  head  of  the  gastrocnemius  and  plantaris 
muscle,  internally  by  the  inner  head  of  the  gastrocnemius.  The  space  contains, 
in  a  variable  amount  of  fat  and  connective  tissue  : 

1.  The  terminus  of  the  short  saphenous  vein  in  the  popliteal. 

2.  The  descending  branch  of  the  small  sciatic  nerve.     (Fig.  260.) 

3.  The  communicating  branches  to  the  short  saphenous  nerve. 

4.  The  internal  popliteal  nerve  in  the  centre  of  the  popliteal  space.     (Fig.  266.) 

5.  The  external  popliteal  nerve  with  the  biceps  tendon. 

6.  The  articular  branch  of  the  obturator  nerve  to  the  knee. 

7.  The  popliteal  artery  and  vein  and  their  branches. 

In  figure  255  note  in  particular  the  formation  of  the  short  or  external 
saphenous  nerve,  by  the  union  of  two  communicating  branches,  from  the  inter- 
nal and  external  popliteal  nerves.  There  is  no  constant  level  at  which  this  union 
takes  place  between  the  communicans  tibialis  and  the  communicans  fibularis. 

Locate  tlie  popliteal  space. 

It  occupies  the  lower  posterior  one-third  of  the  thigh  and  the  upper  poste- 
rior one-sixth  of  the  leg  ;  it  extends  from  the  aperture  in  the  adductor  magnuj 
muscle  to  the  lower  border  of  the  popliteus  muscle. 

dire  tlic  relation,  in  tlic  centre' of  tlie  space,  of  the  internal  popliteal  ncri-c,  and 
tlie  popliteal  vein  an<l  artery.  (Fig.  261.) 

The  nerve  is  above,  the  vein  in  the  middle,  and  the  artery  below.   (Fig.  269.) 

Remember,  when  we  dissect  the  popliteal  space,  the  subject  is  face  downward, 
hence  the  order  referred  t<>  is  as  follows  :  having  cut  through  the  skin,  super- 
ficial fascia,  and  deep  fascia,  called  in  this  region  popliteal  fascia,  the  most  super- 
ficial structure  seen  in  the  space  under  the  deep  fascia  is  the  internal  popliteal 
nerve;  the  next  deep  structure  immediately  under  the  nerve  is  the  popliteal 
vein  ;  the  third  deep  structure  is  the  popliteal  artery.  This  relation  of  the  vein 
to  its  artery  is  in  harmony  with  the  rule  governing  the  relation  of  arteries 
their  veins,  above  and  below  the  diaphragm. 


POSTERIOR   PART   OF  LOWER   EXTREMITY. 


367 


Why  this  relation  of  artery  and  vein  ? 

The  rule  is  :  Veins  are  behind  their  arteries  below  the  diaphragm,  and  in 
front  of  them  above  the  diaphragm — where  they  are  not  on  the  same  plane. 
Exception  to  rule  :  the  renal  vessels. 

What  can  yon  say  about  the  internal  popliteal  nerve  ?     (Fig.  266.) 

It  begins  at  the  bifurcation  of  the  great  sciatic,  and  ends  at  the  lower  border 
of  the  popliteal  space,  where  its  continuation  through  the  leg  is  called  posterior 
tibial.  In  its  course  it  throws  off  these  branches  : 

i.  The  communicans  tibialis  or  communicans  poplitei. 


LAST 
THORACIC 
ILIO-HYPO- 
GASTRIC 


EXTERNAL 

CUTANEOUS 


EXTERNAL 
CUTANEOUS 


COMMUNI- 
CANS 
FIBULARIS 


SHORT 
SA  PHENOL'S 


POSTERIOR 
BRANCHES 
OF  LUMBAR 
NERVES 

POSTERIOR 
BRANCHES 
OF  SACRAL 
NER  VES 

PERFORATING 
CUTANSOU8OF 

SECOND  AND 
THIRD  SACRAL 

LONS 
PUDENDAL 

BRANCHES  OF 
SMALL 
SCIATIC 

OBTURATOR 


POSTERIOR 
BRANCH  OF 
INTERNAL 
CUTANEOUS 

CO.VMUNI- 
CANS 
TIBIALIS 


TWIGS  FROM 
LONG 
S A  PHENOL'S 


INTERNAL 
CALCANEAN 


FIG.  255. — DISTRIBUTION  OF  CUTANEOUS  NERVES  ON  THE  POSTERIOR  ASPECT  OF  THE 

INFERIOR  EXTREMITY. 


2.  Three  articular  branches  to  the  knee-joint. 

3.  Muscular  branches  to  the  gastrocnemius,  soleus,  plantaris,  popliteus. 
The  articular  branches  reach  the  knee-joint  how  ? 

One  goes  with  the  azygos  artery,  and  two  accompany  the  internal  articular 
arteries,  superior  and  inferior. 

Describe  the  external  popliteal  nerve. 

It  begins  at  the  bifurcation  of  the  great  sciatic,  is  found  in  the  outer  side  of  the 
popliteal  space  in  the  sheath  of  the  biceps  muscle.  It  leaves  the  space  between 
the  biceps  and  the  outer  head  of  the  gastrocnemius  muscle.  It  crosses  the  neck 
of  the  fibula,  having  passed  behind  the  head  of  this  bone,  and  terminates  in  the 
anterior  tibial  and  musculo-cutaneous  nerves.  In  its  course  it  gives  off  these 


368 


PR  A  CTJCAL    ANA  TOMY. 


Oluteus  medius  — 


Aponeuroeis  of  eluteus  maxjmus 


Vaatua  externus 


Gluteua  maximus 


Peroneua  longui 


Semi-membranoaus 


Semi-tendinosus 


Gracilis 

Tendon  of  semi-membranosas 


Sartoiiua 


Flexor  longus  difcitorum 


Tendo  Achillii 


KM:.  256.— Sri'KKi  i.  IAI    MK.M  i  K>  01    mi.    i:.\<  K  (i    nn    '1'iiu.ii  AND  LEG. 


POSTERIOR   PART   OF  LOWER   EXTREMITY.  369 

\ 

branches  :   (i)  The  communicans  fibularis  or  communicans  peronei ;    (2)  three 
articular  branches  to  the  knee.      (Fig.  264.) 

77*6'  articular  branches  reach  the  joint  how  ? 

One  goes  with  the  anterior  tibial  recurrent  artery.  Two  accompany  the 
external  articular  arteries,  superior  and  inferior.  Remember,  nerve  trunks  that 
supply  muscles,  supply  the  skin  covering  the  muscles,  and  the  joints  the  muscles 
move. 

Describe  the  popliteal  artery. 

It  extends  from  the  aperture  in  the  adductor  magnus  muscle,  to  the  lower 
border  of  the  popliteus  muscle.  It  is  a  continuation  of  the  superficial  femoral 
artery.  In  its  course  it  gives  off  these  branches  :  (i)  Muscular  to  the  borders  of 
the  popliteal  space  ;  (2)  articular  branches,  five  in  number,  called  superior  two 
(internal  and  external),  inferior  two  (internal  and  external),  and  one  called  the 
azygos.  These  arteries,  as  above  indicated,  are  all  accompanied  by  articular 
nerves  from  the  popliteal  branches  of  the  great  sciatic  nerve. 

Short  saphenons  nerve  is  iiow  formed,  and  where  distributed  / 

It  is  formed  by  the  union  of  the  communicans  tibialis  and  communicans 
fibularis  branches  of  the  internal  and  external  popliteal  nerves  respectively,  and 
distributed  to  the  posterior  part  of  the  leg  and  to  the  outer  border  of  the  foot. 

///  how  many  zvays  is  the  scmimcmbranosns  muscle  inserted? 

In  two  ways  :  (i)  Tendinously,  into  the  inner  tuberosity  of  the  tibia  ;  (2)  apo- 
neurotically,  in  (a)  ligament  of  Winslow,  (<$)  into  internal  lateral  ligament  of  the 
knee,  (r)  into  the  oblique  line  of  the  tibia,  as  the  popliteal  aponeurosis.  Notice, 
aponeuroses  are  named  according  to  the  name  of  the  muscle  they  cover  or 
the  surgical  area  they  invest — e.  g.,  axillary,  masseter,  parotid,  etc. 

Explain  tlie  insertion  of  the  gracilis,  semitendinosus,  and  sartorius. 

They  are  inserted  into  the  upper  one-third  of  the  inner  surface  of  the  tibia, 
below  the  tuberosity  ;  the  gracilis  and  semitendinosus  by  tendon,  the  former  one- 
half  inch  the  higher.  The  sartorius  is  inserted  by  a  broad  aponeurosis,  which 
completely  covers  in  the  insertions  of  the  other  two  muscles. 

The  ] icads  of  the  gastrocnemius  differ  in  origin  how  / 

The  inner  head  arises  above  the  condyle  ;  the  outer,  from  the  side  of  the 
condyle.  The  latter  seems  to  have  been  crowded  out  of  place  by  the  plantaris 
muscle — at  least  let  this  suggestion  aid  the  memory. 

Geometrical  Inventory  of  the  Popliteal  Space  : 

Roof — skin,  superficial  and  deep  fasciae. 

Floor — femur,  ligament  of  Winslow,  popliteus  muscle. 

Superior  end — aperture  in  the  adductor  magnus  muscle. 

Inferior  end — oblique  line  of  the  posterior  surface  of  the  tibia. 

Superior  border — externally,  the  biceps  muscle. 

Superior  border — internally,  semitendinosus,  semimembranosus,  gracilis,  and 
sartorius  muscles. 

Inferior  border — internally,  inner  head  of  the  gastrocnemius. 

Inferior  border — externally,  outer   head  of  the  gastrocnemius  and  plantaris. 

Shape — diamond  ;  resembling  two  triangles  with  bases  together. 

In  the  center  are  seen  the  internal  popliteal  nerve  and  popliteal  vessels. 

Outer  border — the  external  popliteal  nerve  is  in  the  sheath  of  biceps. 


370 


PRACTICAL   ANATOMY. 


THE  GLUTEAL  REGION. 

The  gluteus  maximus  muscle  (Eig.  256)  must  now  be  put  on  the  stretch 
by  rotating  the  entire  limb  inward,  and  at  the  same  time  drawing  the  subject  to 
the  edge  of  the  table  and  slightly  lowering  the  leg.  Now,  with  a  sharp  scalpel 
remove  the  deep  fascia  from  the  muscle  itself  (Fig.  257),  and  locate  the  line  of 
differentiation  between  the  gluteus  maximus  and  medius.  Theoretically,  this  is 
easily  done,  but  practically  some  experience  is  necessary  to  obtain  perfect  results, 
since  the  gluteal  aponeurosis  continues  forward  and  completely  covers  the  gluteus 
medius  muscle.  The  gluteus  maximus  originates  :  (i)  From  the  aponeurosis  of 
the  gluteus  medius  ;  (2)  from  the  lumbar  aponeurosis  and  the  greater  sacro-sciatic 
ligament ;  (3)  from  the  side  of  the  coccyx  ;  (4)  from  the  back  of  the  lateral  part 


FIG.  257. — GLUTEUS  MAXIMUS  MUSCI.K. 
I.   Gluteus  maximus.      2.    Its    inferior    portion.      3.    Fibres  of  attachment  to  linea    aspera.      4.    Superior 
portion.     5,  5.   Tendinous  fibres  of  insertion  into  linea  aspera.     6.    Upper  portion  of  femoral  apo- 
neurosis.    7.   Duplicature  of  this  aponeurosis  at  superior  level  of  gluteus  maximus.     8.   Portion  of 
its   superficial  layer  attached  to  tendinous  bands.     9.   Lower   extremity  of  tensor   vaginae  femoris. 

10,  IO.    Portion    of  femoral    aponeurosis   continuous    with    tendinous    fibres    of    gluteus    maximus. 

11.  Upper  portion  of  biceps  femoris.     12.   Upper  portion  of  semitendinosus.      13.    Upper  portion  of 
seminiembranosus.      14.   Gracilis. 


of  the  lower  two  segments  of  the  sacrum  ;  (5)  from  the  posterior  one-fifth  of  the 
outer  lip  of  the  iliac  crest ;  (6)  from  the  surface  of  the  bone  between  the  crest  of 
the  ilium  and  the  superior  gluteal  ridge.  ( l;ig.  226.)  The  muscle  is  inserted 
into:  (i)  The  ilio-tibial  band;  (2)  into  the  gluteal  ridge  of  the  femur.  (Fig. 
227.)  The  inferior  gluteal  nerve,  a  branch  of  the  sacral  plexus,  supplies  this 
muscle. 

Cut  at  its  insertion  into  the  deep  fascia  of  the  thigh,  and  into  the  gluteal 
ridge  of  the  femur,  the  gluteus  maximus  ;  turn  tin-  same  back,  as  seen  in  figure 
258.  Also  cut  the  insertion  of  the  gluteus  medius  at  the  oblique  line  of  the 
greater  trorhanter  (Fig.  227),  turn  same  up.  and  develop  your  work  like 
figures  258  and  259.  Caution!  Take  the  greatest  care,  in  turning  the 


POSTERIOR  PART   OF  LOWER   EXTREMITY.  371 

above  muscles  back,  not  to  injure  the  vessels  and  nerves,  upon  which  both 
the  beauty  and  benefit  of  your  dissection  depend.  You  have  exposed  to  view 
now  these  structures  : 

1.  The  greater  sacro-sciatic  foramen.      (Fig.  226.) 

2.  The  lesser  sacro-sciatic  foramen.     (Fig.  226.) 

3.  Sacro-sciatic  ligaments — greater  and  lesser.      (Fig.  258.) 

4.  The  three  gluteal  muscles. 

5.  The  pyriformis  muscle. 

6.  The  obturator  externus  muscle. 

7.  The  obturator  intern  us  muscle. 

8.  The  gemelli — superior  and  inferior. 

9.  The  quadratus  femoris  muscle. 

10.  The  superior  gluteal  nerve  and  artery. 

1 1.  The  small  sciatic  nerve  and  its  branches. 


Sciatic  artery 


INFERIOR  GLUTEAL  NERVE 
Gluteal  artery 


Gluteus 

medius 


Gluteus  maximus 


BRANCH  TO  GLl'- 
TEUS  MAXIMUS 


Tendon  of  obturator  externu3 

Vastus  externus  Gluteus  maximus 

FIG.  258. — A  DISSECTION  OF  THE  NERVES  IN  THE  GLUTEAL  REGION. 
(The  gluteus  maximus  and  glutens  medius  have  been  divided  near  their  insertions,  and  thrown  upward.) 

12.  The  sciatic  artery  and  its  branches. 

13.  The  great  sciatic  nerve  and  its  relations. 

14.  The  internal  pudic  nerve  and  artery. 

15.  The  origin  of  the  biceps,  semitendinosus,  and  semimembranosus. 

1 6.  The  gluteus  medius  muscle. 

17.  The  gluteus  minimus  muscle. 

1 8.  The  subgluteal  bursa  over  the  greater  trochanter. 

The  gluteus  medius  arises  from  the  outer  lip  of  the  iliac  crest  for  the  anterior 
four-fifths  ;  from  the  outer  surface  of  the  ilium,  between  the  superior  and  middle 
gluteal  curved  lines  (Fig.  226)  ;  from  the  dense  aponeurosis  covering  the  muscle 
and  separating  the  same  from  the  gluteus  maximus.  The  muscle  is  inserted  into 
the  oblique  line  of  the  greater  trochanter  of  the  femur.  (Fig.  227.)  Nerve-supply 
is  the  superior  gluteal  from  the  lumbo-sacral  cord  of  the  sacral  plexus.  (Fig.  193.) 

The  gluteus  minimus  arises  from  the  outer  surface  of  the  ilium,  between  the 


372  PRACTICAL   ANATOMY. 

middle  and  the  inferior  curved  gluteal  lines  (Fig.  226),  from  the  capsule  of  the  hip, 
and  is  inserted  into  the  anterior  border  of  the  greater  trochanter.  (Fig.  228.)  The 
nerve-supply  is  from  the  superior  gluteal.  (See  page  28 1 ,  Superior  Gluteal  Nerve.) 

Notice  the  common  origin  of  the  long  head  of  the  biceps  and  semitendin- 
osus  from  the  tuber  of  the  ischium.  (Fig.  226.)  See  where  the  semimem- 
branosus,  in  its  origin  from  the  tuber,  crosses  the  two  preceding  muscles  since 
it  arises  from  the  upper  and  outer  part  of  the  tuberosity. 

Greater  Sacro-sciatic  Foramen. — The  notch  of  the  same  name  (Fig.  226) 
is  converted  into  this  foramen  by  the  lesser  sacro-sciatic  ligament.  It  transmits 
the  pyriformis  muscle,  which  divides  the  foramen  into  an  upper  and  a  lower  com- 
partment. (Fig.  258.)  Above  the  muscle  emerge  the  superior  gluteal  artery  and 
nerve  ;  below  the  muscle,  the  greater  sciatic  nerve,  the  lesser  sciatic  nerve,  the 
sciatic  artery,  the  internal  pudie  ncn'c  and  artery,  and  the  inferior  gluteal  nerve. 

The  pyriformis  muscle  arises  from  the  anterior  surface  of  the  sacrum,  be- 
tween the  four  upper  anterior  sacral  foramina.  The  muscle  leaves  the  pelvis  by 
the  greater  sacro-sciatic  foramen,  and  is  inserted  into  the  upper  border  of  the 
greater  trochanter. 

The  Gluteal  Artery  (Fig.  258). — The  largest  branch  of  the  internal  iliac; 
leaves  the  pelvis  by  the  greater  sacro-sciatic  foramen,  above  the  pyriformis, 
divides  into  a  superficial  and  a  deep  branch.  The  former  lies  between  the  glutens 
maximus  and  medius,  and  anastomoses  with  the  circumflex  iliac  branch  of  the 
external  iliac  artery  ;  the  latter — the  deep  branch — lies  between  the  gluteus 
medius  and  minimus,  and  anastomoses  with  the  external  circumflex  artery, — a 
branch  of  the  prof un da. 

The  superior  gluteal  nerve — a  branch  of  the  lumbo-sacral  cord  of  the  sacral 
plexus — accompanies  the  artery  of  like  name  (Fig.  258)  and  supplies  the  gluteus 
medius  and  minimus  and  the  tensor  vaginae  femoris. 

The  Sciatic  Artery  (Fig.  258). — A  branch  of  the  internal  iliac.  It  leaves 
the  pelvis  below  the  pyriformis  muscle.  It  gives  branches  to  the  rectum,  base 
of  bladder,  seminal  vesicles,  prostate,  and  all  the  muscles  of  the  pelvic  floor. 
It  sends  branches  to  the  muscles  on  the  back  of  the  hip  ;  one  branch,  the  comes 
neri'i  iscJdadici,  to  the  great  sciatic  nerve.  (Fig.  258.)  It  anastomoses  with  the 
gluteal,  the  obturator,  both  circumflex  arteries,  internal  and  external,  and  with 
the  superior  perforating  artery,  a  branch  of  the  profunda  femoris. 

The  Great  Sciatic  Nerve  (Fig.  193). — The  largest  branch  of  the  sacral 
plexus.  Leaves  the  pelvis  below  the  pyriformis.  Lies  upon  successively  the 
superior  gemellus,  the  internal  obturator,  the  inferior  gemellus,  the  external 
obturator,  the  quadratus  femoris,  and  the  adductor  magnus.  (Fig.  258.)  It  ends 
in  the  popliteal  space,  in  the  internal  and  external  popliteal  nerves.  It  gives 
motor  branches  to  the  biceps,  semitendinosus,  semimembranosus,  and  adductor 
magnus  muscles.  It  gives  to  the  hip-joint  articular  branches,  which  perforate 
the  posterior  part  of  the  capsule. 

The  Small  Sciatic  Nerve  (Fig.  260). — A  branch  of  the  sacral  plexus. 
(  Fig.  193.)  It  leaves  the  pelvis  below  the  pyriformis  muscle,  lying  behind  the 
greater  sciatic  nerve.  Its  branches  are  cutaneous  :  ascending,  internal,  external 
and  descending.  The  latter  passes  through  the  popliteal  space  to  supply  the 
skin  over  the  insertion  of  the  flexors  of  the  leg.  (Fig.  255.)  The  small  sciatic 
is  then  the  great  divoircd  sensory  branch  of  the  great  sciatic,  carrying  out 
Hilton's  law.  The  internal  branches  of  this  nerve  are  numerous.  (Fig.  260.) 
The  short  ones  supply  the  skin  on  the  inner  side  of  the  thigh  ;  the  longest  one 
of  the  internal  branches  is  called  the  inferior  pudenda!,  or  nerve  of  Sdemmering, 
and  supplies  tin-  scrotum  and  labia  majora. 

How  to  find  the  long  pudendal  in  practical  anatomy  :  It  crosses  the  tendons 
of  the  biceps  and  semitendinosus,  on  the  tuber  of  the  ischium.  (Fig.  260.) 


POSTERIOR   PART   OF  LOWER   EXTREMITY. 


373 


The  Inferior  Gluteal  Nerve. — A  branch  of  the  sacral  plexus.  Leaves  the 
pelvis  by  the  greater  sacro-sciatic  foramen,  below  the  pyriformis,  and  supplies 
the  gluteus  maximus.  (Fig.  258.) 

The  Lesser  Sacro-sciatic  Foramen. — The  notch  of  the  same  name  is  con- 


Gluteus  medius 

Pyriformis 
Gemellus  superior 

Gemellus  inferior 
Quadratus  femoris 


Gluteua  maximus 


Vastus  externus 

Biceps 


Crureus 

Short  head  of  biceps 
Plantaris 


Oastroonemiue 


Obturator  interims 


Adductor  magnuS 


FIG.  259. — THE  EXTERNAL  ROTATORS  AND  THE  HAMSTRING  MUSCLES. 


verted  into  this  foramen  by  the  greater  sacro-sciatic  ligament.  (Fig.  259.)  It  trans- 
mits the  internal  obturator  tendon  and  its  nerve,  the  internal  pudic  nerve,  artery, 
and  vein.  (Fig.  258.)  The  vessels  and  nerve  lie  above  the  tendon.  To  trace  these 
structures  properly,  it  will  be  necessary  to  remove  the  gluteus  maximus  from  the 


374 


PRACTICAL  ANATOMY. 


greater  sacro-sciatic  ligament,  and  then  cut  the  latter.     You  \vill  then  see  the 
internal  pudics  all  entering  Alcock's  canal.     (Fig.  258.) 

Branches  and  Course  of  Internal  Pudic  Nerve. — A  branch  of  the  sacral 
plexus.  (Fig.  194.)  The  nerve  escapes  from  the  pelvis  by  the  greater  sacro- 
sciatic  foramen,  crosses  the  spine  of  the  ischium,  enters  the  pelvis  by  the  lesser 
sacro-sciatic  foramen  (Fig.  226),  above  the  tendon  of  the  obturator  internus 
muscle,  traverses  a  delamination  of  the  obturator  fascia,  called  Alcock's  canal,  in 


Gluteus  uiedius 


Gluteus  minimus 

Pyriformis,  divided 

into    two    by    the 

great  sciatic  nerve 

GREAT  TROCHANTER 

Obturator  ezternus 


Quadratus  femoris 


Faacial  insertion  of 
gluteus  mazimus 


Horizontal  fibres  of 
adductor  inagnus 


Fleshy  insertion  of 
gluteus  mazimus 


GREAT  SACRO-SCIATIC 
FORAMEN 

GLUTEAL  NERVE 
SUPPLYING  POR- 
TIONS OF  GLU- 
TEUS MEIHUS 

GHuteus  mazimus 


Obturator  interims. 
Below  is  the  infe- 
rior gemellus.  The 
superior  gemellus 
is  absent 


BRANCHES  Of-'  J\- 
FER10I! 
DAL  NERVE 


GKEAT  SCIATIC  NEKVE. 
Under  it,  oblique  fibres  of 
adductor  magnus  are  seeu 


SMA  LL  SCI  A  TIC  NER  VB 


FIG.  260. — DEEP  DISSECTION  OK  THI    <;i.>  n  \\    Kuans. 
(From  a  preparation  in  the  Hunterian  Museum.) 


the  outer  wall  of  the  ischio-rectal  fossa.  It  gives  off  the  following  branches  : 
(l)  The  inferior  liu'inorrlioidal,  which  crosses  the  ischio-rectal  fossa  and  supplies 
the  skin  around  the  anus  ;  (2)  the  perinea!,  which  supplies  tin-  integument  of 
tlu-  scrotum  and  tin-  labia  majora,  the  transversus  perin;ei,  the  accelerator  urina/, 
the  erector  penis,  and  the  compressor  urethne,  or  deep  internal  transversus  perinaei 
muscle;  (3)  the  dorsal  nerre  of  the  penis,  which  gives  off  branches  to  the  skin 
of  the  penis,  and  to  the  corpus  cavernosum. 


POSTERIOR   PART   OF  LOWER   EXTREMITY.  375 

Greater  Trochanter  (Figs.  227  and  228). — Muscles  inserted  into:  (i)  The 
glutens  inedins  into  the  oblique  line.  (2)  The  glutens  minimus  into  the  anterior 
surface.  (3)  The  obturator  externus  into  the  digital  fossa.  (4)  Into  the  superior 
border,  in  the  following  order,  from  before  backward  :  the  pyrifonnis,  the  gcuuihis 
superior,  the  obturator  interims,  and  the  gcmellus  inferior.  This  is  the  logical 
order  of  insertion,  since  they  leave  the  pelvis  in  this  order.  (5)  Into  the  base 
you  will  see  the  vastus  externus.  (Fig.  228.)  Now  turn  to  figures  227  and 
228  and  study  these  insertions  on  the  bone.  In  your  dissection  trace  each 
tendon  to  its  complete  insertion. 

Gluteus  Maximus  Insertion. — This  muscle  is  inserted  into  the  gluteal 
ridge  of  the  femur.  This  is  called  the  third  trochanter  when  it  is  very  large. 
It  is  one  of  the  constituent  parts  of  the  linea  aspera.  Turn  to  figure  227,  and 
study  the  linca  aspera.  (Read  page  329  on  linea  aspera.) 

External  Rotators  of  the  Thigh. — From  the  nature  of  the  origin  and  in- 
sertion of  the  pyriformis,  gemelli,  obturators,  and  quadratus  femoris,  they  will 
produce  external  rotation  of  the  limb,  when  this  is  straight — that  is,  when  its 
long  axis  parallels  the  long  axis  of  the  trunk,  as  in* the  standing  or  recumbent 
posture.  In  the  sitting  posture,  however,  when  the  limb  is  at  right  angles  to  the 
trunk,  they  make  'traction  parallel  to  the  long  axis  of  the  femur,  and  thereby 


PATELLA  

Synovial  membrane  — 


Capsule  - 

FEMUR  — 


Crucial  ligaments  — ! 

Vt^iHBfitoffiiS!  SSMP.W—  Inner  head  of  gastroccemius 

Biceps  — ^liisSFQm^SF^r"' Sartorius 

Outer  head  of  gastroonemius  - :S«^;C!>^  5&ffiP^<?- Gracilis 

Popliteal  artery  — 

EXTERNAL  POPLITEAL  NERVE  ^^  ^" *^     ^Sem.-membranosus 

Popliteal  rein ' 
INTERNAL  POPLITEAL  NERVE  /  Semi-tendinosua 

External  saphena  vein 

FIG.  261. — HORIZONTAL  SECTION  OF  THE  KNEE-JOINT.     (One-half.) 

become  physiological  abductors  and  antagonize  the  adductor  group.  The  obtura- 
tor externus  remains  an  external  rotator  even  in  the  sitting  position.  Pull  the 
cadaver  to  the  edge  of  the  table,  and  make  this  simple  demonstration  at  this 
stage  of  your  dissection. 

Demonstrate  on  yourselves  external  rotation  (i)  in  the  standing  position  ; 
(2)  in  the  sitting  position.  In  the  first  case  notice  the  ease  with  which  you  may 
turn  the  whole  limb  outward.  This  act  was  done  with  ease  because  the  six 
external  rotators  participated  in  the  act.  It  would  be  very  much  more  difficult 
to  do  if  five  of  these  refused  to  act.  This  is  exactly  what  occurs  when  you  sit 
and  do  external  rotation,  since  five  of  these  muscles  cease  to  be  external  rotators 
when  exerting  traction  in  the  long  axis  of  the  limb,  as  they  do  in  the  sitting 
posture.  In  the  standing  position  six  muscles  are  exerting  traction  in  the 
region  of  the  greater  trochanter  almost  at  right  angles  to  the  long  axis  of  the 
femur.  This  makes  external  rotation  easy.  In  sitting,  only  one  muscle  is  left 
to  do  this  work — /.  e.,  the  external  obturator  muscle. 

Internal  Rotators  of  the  Thigh. — The  anterior  segments  of  the  glutens 
mcdins  and  miniums  rotate  the  thigh  inward. 

Tendon  of  Obturator  Internus. — To  show  this  tendon,  carefully  separate  the 


376 


PRACTICAL  ANATOMY. 


FIG.  262. — SHORT  HEAD  OF  BICEPS  AND  SEMI- 
MEMBRANOSUS. 

I.  Attachment  to  ischium  of  long  head  of  biceps 
and  semitendinosus.  2.  Se  m  i  mem  bran  osus.  3. 
Its  superior  tendon.  4.  Its  inferior  tendon.  5. 
Middle  portion  of  tendon.  6.  Its  anterior  por- 
tion. 7.  Its  posterior  portion.  8.  Section  of 
long  head  of  biceps.  9.  Its  short  head.  10. 
Its  attachment  to  head  of  fibula.  II,  II,  II. 
Adductor  magnus.  12,  12.  Orifices  for  passage 
of  perforating  arteries  and  veins.  13.  Vastus 
externus.  14,  14.  Insertion  of  glutens  maximus. 
15.  Divided  expansion  of  tendon  of  this  muscle, 
continuous  with  the  aponeurosis  of  the  vastus 

•  externus.  16.  Attachment  <>!"  quadratus  fenu>ri>. 
17.  Tendon  of  obturator  externus.  18.  Attach- 
ment of  glutens  medius.  19.  Obturator  internus. 
20.  Tendon  of  pyramidalis.  21.  (Unions  mini- 
mus. 22.  Divided  inner  ln-ad  of  gastrocnrmiiis. 
23.  Outer  head.  24.  Plantaris.  25.  Popliteus. 
26.  Soleus.  27.  Fibrous  ring  for  artery,  vein, 
and  nerve. 


FIG.  263. — LONG  HEAD  OF  BICEPS  AND  SEMI- 
TENDINOSUS. 

I.  Long  head  of  biceps.  2.  Common  tendon  of 
head  of  biceps  and  semitendinosus.  3.  Inferior 
tendon  of  biceps.  4.  Semitendinosus.  5.  Its 
tendon.  6,  6.  Its  tendinous  expansions,  con- 
tinuous with  aponeurosis  of  leg.  7.  Semimem- 
branosus.  8.  Its  inferior  tendon.  9.  Gracilis. 
10.  Its  tendon.  II.  Sartorius.  12.  Vastus  ex- 
ternus. 13.  Femoral  attachment  of  gluteus  maxi- 
nuis.  14.  Insertion  of  gluteus  medius.  15. 
(ilnteus  minimus.  16.  Tendon  of  pyriformis. 
17.  Obturator  internus.  18.  Quadratus  femori.-. 
19.  Inner  head  of  gastrocnemius.  20.  Outer 
Ix-ud  of  gastrornrmius.  21.  Plantaris.  22. 
Popliteal  apqneurosis. 


POSTERIOR   PART   OF  LOWER    EXTREMITY.  377 

muscle  above  and  below  from  the  gemelli.  (Fig.  259.)  Cut  the  muscle  near  its 
insertion  into  the  greater  trochanter,  and  then  trace  it  back  into  the  pelvis 
through  the  lesser  sacro-sciatic  foramen.  Notice  the  strong  converging  tendin- 
ous bands  on  the  under  surface  of  the  muscle.  Also  see  the  origins  of  the 
gemelli  from  the  ischial  tuber  and  spine.  (Fig.  226.) 

Reduced  to  its  simplest  terms,  wliat  is  a  rational  pliysiological  grouping  of  tlie 
muscles  primarily  concerned  in  the  movements  of  t lie  1  tip-joint? 

(i)  Flexors  of  the  thigh  on  the  abdomen  ;  (2)  extensors  of  the  thigh  on  the 
abdomen  ;  (3)  adductors  of  the  thigh  on  the  pelvis  ;  (4)  abductors  of  the  thigh 
on  the  pelvis  ;  (5)  internal  rotators  of  the  thigh  ;  (6)  external  rotators  of  the 
thigh. 

Xamc  the  flexor  muscles  of  tlic  tJiigh. 

The  iliacus  and  psoas  magnus,  inserted  into  the  lesser  trochanter  of  the  femur, 
are,  as  Morris  points  out,  almost  pure  flexor  muscles.  When,  however,  they 
deviate  from  flexion,  they  are  to  some  extent  internal  rotators,  and  not,  as  is 
sometimes  suggested,  external  rotators.  Nerve-supply,  second  and  third  lumbar 
nerves. 

Hoiv  is  tlie  t/iig/i  extended  on  the  pelvis  / 

By  the  action  of  the  gluteus  maximus,  which  is  the  direct  antagonist  of  the 
psoas  and  iliacus.  Nerve-supply,  the  inferior  gluteal  nerve. 

Name  the  abductors  of  tJie  hip-joint. 

The  tensor  vaginae  femoris,  the  gluteus  medius,  the  gluteus  minimus. 
Nerve-supply,  superior  gluteal. 

Name  t/ie  adductors  of  the  t/iigh  or  hip-joint  / 

The  obturator  externus,  the  adductor  longus,  the  adductor  brevis,  the  adduc- 
tor magnus,  and  the  adductor  gracilis.  Nerve-supply,  the  obturator. 

How  is  tJie  t/iig/t  or  /tip-joint  rotated  inward  ? 

By  the  anterior  segments  of  the  members  of  the  abductor  group  of  muscles — 
viz.,  the  glutei  minimus  and  medius  and  the  tensor  vaginae  femoris  ;  and,  in  addition, 
according  to  Morris,  by  the  ilio-psoas  muscle.  Nerve-supply,  superior  gluteal. 

Name  the  muscles  that  rotate  the  thigh  outward. 

The  pyriformis,  the  obturator  internus,  the  two  gemelli  muscles,  and 
the  quadratus  femoris.  These  muscles  all  derive  their  nerve-supply  from  the 
sacral  plexus.  The  obturator  externus,  although  strictly  speaking  an  adductor 
muscle,  becomes  an  external  rotator  when  the  patient  is  in  the  sitting  posture. 

Now,  on  figure  263  study  the  relation  of  the  quadratus  femoris,  obturator 
internus,  and  the  gemelli  to  each  other.  On  figure  262,  on  which  the  quadratus 
and  gemelli  are  removed,  study  the  relation  of  the  obturators  to  each  other. 


BACK  PART  OF  THE  LEG. 

Locate  the  fibrous  arch  connecting  the  heads  of  the  gastrocnemius  muscle. 
(Fig.  259.)  Notice  passing  downward  into  the  deep  intermuscular  space  the 
popliteal  artery  and  vein,  in  their  proper  relation  to  each  other,  and  the  internal 
popliteal  nerve.  (Fig.  264.)  Carefully  isolate  these  structures  from  each  other 
and  from  the  arch.  Then  lift  the  arch  upward  and  cut  down  between  the  two 
heads  of  the  gastrocnemius  to  the  point  where  this  muscle  joins  the  soleus.  Also 
notice  between  these  two  muscles  the  plantaris,  with  its  very  long  tendon.  (Fig. 
264.)  Now  cut  the  gastrocnemius  (Fig.  264),  and  trace  each  head  across  the 
joint  to  its  exact  origin  on  the  femur.  (Fig.  227.)  Notice  the  difference  in  origin 
25 


378 


PRACTICAL  ANATOMY. 


on  the  two  sides.  Also  trace  the  plantaris  up  to  its  origin — and  be  sure  you  find 
its  nerve,  a  branch  of  the  internal  popliteal.  (Fig.  264.) 

Locate  the  fibrous  arch  of  the  soleus.  (Fig.  264.)  See  passing  under  the 
same  the  popliteal  artery,  nerve,  and  vein,  now  called  posterior  tibial,  as  far  clown 
as  the  ankle,  having  passed  under  the  arch  of  the  soleus.  Pull  the  arch  up  and 
cut  down  between  the  two  heads  of  the  soleus.  By  cutting  in  the  mid-line  of 
these  two  muscles  you  preserve  the  nerve-supply  intact,  which  nerves  it  is  desired 
you  trace  out  carefully.  You  will  remember  the  gastrocnemius,  plantaris,  soleus, 
and  popliteus  are  supplied  by  the  internal  popliteal  nerve.  (Fig.  264.)  Now 
let  your  dissection  verify  the  complete  distribution  of  the  internal  popliteal  nerve. 
Preserve  every  branch  of  this  nerve. 

On  each  side  of  the  fibrous  arch  of  the   soleus,  on   the   tibia  and  fibula,  you 


Adductor  magnua 

Popliteal  vein 
Popliteal  artery 

INTERNAL  POPLITEAL  NERVE 

Vastus  interims 

Superior  internal  articular  artery 

Tendon  of  semi-membranosus 

Inner  head  of  gastrocnemius 

Inferior  internal  articular  arler. 
Popliteal  vein 
Popliteui 


Tendon  of  plantaris 


Vastuu  eiternus 

GRKA  T  SCTA  TIC  SERVE 

Short  head  of  biceps 
EXTERNAL  POPLITEAL  SERVE 


Long  head  of  biceps,  out 
Outer  head  of  gastrocnemius 


COMMVNICAN8  PEROXEI  XI-:J:VE 


-  Soleus 


Qastrocnemius 


External  saphenous  vein  and  nerve 
FIG.  264. — DEEP  VIEW  OF  THE  POPLITEAL  SPACE.     (Hirschfeld  and  Leveille.) 


will  see  the  inner  and  outer  heads  of  this  muscle.  (Fig.  208.)  Divide  them 
carefully  one-half  of  an  inch  from  their  origin,  and  turn  the  three  muscles  of  the 
superficial  group  aside,  and  figure  266  will  represent  what  you  should  have. 
You  now  have  in  view  these  structures  : 

1.  The  posterior  tibial  nerve  and  its  branches.      (Fig.  266.) 

2.  The  posterior  tibial  vessels  and  their  branches.     (Fig.  266.) 

3.  The  remaining  origins  of  the  plantaris,  soleus,  and  gastrocnemius,  and  the 
popliteus  muscle,  as  seen  in  figure  265. 

4.  The  tibialis  posticus,  an  extensor  muscle  of  the  tarsus. 

5.  The  flexor  longus  digitorum  muscle — a  flexor  of  the  four  outer  toes. 

6.  Tin-  flexor  longus  hallucis  muscle — a  flexor  of  the  great  toe. 

~.    The  thin,  dee])   transverse   fascia,  or  deep  intei  muscular  fascia  of  the  leg, 
which  you  will  now  see  covering  in  all  the  structures  below  the  popliteus  muscle. 


POSTERIOR   PART   OF  LOWER   EXTREMITY. 


379 


If  you  examine  this  fascia,  you  will   find  it  attached  internally  to  the  tibia,  ex- 
ternally to   the  fibula,  and  above  to  the   oblique   line  of  the  tibia.      (Fig.  208.) 


Outer  head  of  gastrocnemiue 


Inner  head  of  gastrocuemius 


Biceps 


'  Tendon  of  semi-metnbrauosus 


PeroneuB  longus 1 


Flexor  longus  hallucis  • 


PopliteuB 


Tibialia  postieus 


Plexor  longus  digitorum 


Peroneus  brevis  . 


Tibialis  postieus 


.  Tendo  Aehillis 


FIG.  265. — THE  DEEP  MUSCLES  OF  THE  BACK  OF  THE  LEG. 


It  is  quite  thin,  yet  strong,  and  permits  the  posterior  tibial  vessels  and  nerves  to 
be  seen  through  it. 

The  Posterior  Tibial  Nerve  (Fig.  266). — It  begins  at  the  lower  border  of 


38o 


PRACTICAL    ANATOMY. 


the  popliteal  muscle  ;  it  is   a  continuation  of  the  internal   popliteal  nerve  down- 
ward.    It  ends  under  the  internal  annular  ligament  (Fig.  266)  of  the  ankle, 


Superior  external  articular  artery 

POPLITEAL  NERVE- 
External  lateral  ligament 

Inferior  external  articular  artery 
Popliteus 

Muscular  branch  to  soleus 
Soleus  • 
Anterior  tibial  artery 

Peroneus  longus  . 
Peroneal  artery . 


BRANCH  OF  POSTERIOR  TIBIAL  . 
NERVE  TO  FLEXOR  LONGUS 
HALLUCIS 

Flexor  lougus  hallucis 


Superior  internal  articular 
Popliteal  artery 

Posterior  ligament  of  knee 

Azygos  articular  artery 

SEMI-MEMBRANOSUS 


Inferior  internal  articular  artery 

Muscitlar  branch 


Tibialis  posticus 

POSTERIOR  TIBIAL  NERVE 


MUSCULAR  BRANCH  OF  POS- 
TERIOR TIBIAL  NERVE  TO 
FLEXOR  LONGUS  D1GITORUM 


Flexor  longus  digitorum 


Posterior  tibial  artery 


Cutaneous  branch  of  peroneal  artery 


Peroneus  breviu 
Continuation  of  peroneal  artery 

OS  CALCIS 


Tibialis  posticus 


(  'iiinmi/n  imthifj  branch 
Internal  annular  ligament 


Internal  calcaneal  artery 


FIG.  266. — RELATIONS  OK  THE  I'ori.n  KAI.  AKTIKY   ro   BONES  AND  Mi  *  US. 

(The  Mriu-tiiiv.-  M-I-II  in  tliis  li^un-  :uv  loveu-.l  liy  ilu-  <ln-|>  n  aii>\  i-rse  fascia.      Sec  P.IL;C  ,i7>-.) 


between   the  internal  inallrohis  and  <>•<   calcis,  h\-   di\iding  into   the  internal   and 
external  plantar  nerves.     (Fig.  272.)     It  accompanies  the  posterior  tibia!  v 

first  to  tin-  inner  and  latrr  to  tlu-  outer  side  of  these  vessels. 


POSTERIOR   PART   OF  LOWER   EXTREMITY. 


POPLITEAL  NOTCH 


External  fibre-cartilage 

Capsule 
Posterior  crucial  ligament 

STYLOID  PROCESS 
Posterior  tibio-ftbular  ligament 


Tibialis  posticus 


Flexor  longus  hallucis 


FLEXOR  SURFACE  OF  FIBULA 


NUTRIENT  FORAMEN 


FIBULA 


Peroneus  brevis 


Posterior  tibio-flbular  ligament 

GROOVE  FOR  FLEXOR  LONGUS  HALLUCIS 

External  lateral  ligament 

(posterior  fasciculus) 

External  lateral  ligament 

(middle  fasciculus) 


Internal  flbro-cartilage 

Capsule 

Semimembranosus 


Popliteus 


OBLIQUE  LINE 
Soleus 


POSTERIOR  SURFACE  OF  TIBIA 


Flexor  lonsus  digitorum 


GROOVE  FOR  TIBIALIS  POSTICUS  AND 
FLEXOR  LONGUS  DIGITORUM 


Internal  lateral  ligament 


Posterior  ligament  of  ankle-joint 

FIG.  267. — THE  LEFT  TIBIA  AND  FIISULA.     (Posterior  view.) 


382 


PRACTICAL  ANATOMY. 


Branches  of  Posterior  Tibial  Nerve. — (i)  An  articular  branch  to  the  ankle, 
given  off  just  above  the  bifurcation  of  the   nerve  into  the  internal  and  external 


POSTERO-INFERIOR  SURFACE  OF  THE 
CALCANEUM 


Abductor  minimi  digit! 
Abductor  oasis  metatarsi  quiuti 


Accessorius  (outer  head) 


Plexor  brevis  hallucis 
Abductor  oasis  metatarsi  quinti 

Flexor  brevis  minimi  digit! 

Adductor  hallucis 
Third  plantar  interosseous 

Second  plantar  interosseous 
First  plantar  interosseous 

Flexor  brevis  minimi  digit! 


Abductor  brevis  minimi 
digiti 

Third  plantar 
interosseous 


Second  plantar 
luterosseoua 


First  plantar  interosseous 


Flexor  brevis  digitorum 
Flexor  lougus  digitorum 


Abductor  hallucis 
Flexor  brevis  digitorum 


Accessorius  <  inner  headi 


Tibialis  posticus 


Tibialls  anticus 
Peroneus loneus 


.ri^ii-i:         Abductor  hallueia 

J    ~K Flexor  brevis  halluoi* 

(inner  portion) 
Flexor  brevis  hallucis 

(outer  portion) 
Adductor  hallucis 
Transversus  pedis 


Flexor  longus  hallucia 


FIG.   268. — Tin.  I.I.KT   FOOT.      (Plantar  surface. ) 
(Study  the  insertion  and  location  of  tendons  on  this  and  compare  your  dissection  therewith.) 

plantar  nerves.  (2)  A  plantar  cutaneous  nerve,  to  the  heel  and  inner  side  of  the 
sole  of  the  foot.  (Fig.  272.)  (3)  Muscular  branches  to  the  tibialis  posticus, 
flexor  longus  hallucis,  and  flexor  longus  digitorum  musoK-s.  ( Fig.  266.) 


POSTERIOR   PART   OF  LOWER   EXTREMITY. 


383 
(Fig. 


Two   terminal  branches — the    internal  and  external  plantar   nerves. 
272.) 

Branches  of  the  Posterior  Tibial  Artery. — (i)  The  peroneal  artery  to  the 
outer  side  of  the  leg.  (Fig.  266.)  (2)  A  nutrient  artery  to  the  tibia,  which  you 
will  find  entering  the  foramen  as  far  down  as  the  lower  end  of  the  oblique  line  of 
the  tibia,  on  the  ridge  separating  the  origin  of  the  tibialis  posticus  from  the  flexor 
longus  digitorum.  (  Fig.  208.)  Find  this  artery  and  recall  the  rule  for  the  direc- 
tion of  these  foramina  in  the  long  bones  of  the  extremities  :  from  the  knee  and 


FIG.  269. — MUSCLES  OF  THE  LEG,  EXTERNAL  ASPECT. 

Tibialis  anticus.  2,  2.  Tendon  of  extensor  proprius  pollicis.  3,  3.  Extensor  longus  digitorum.  4. 
Its  tendons  for  four  last  toes.  5.  Peroneus  tertius.  6.  Its  attachment  to  last  two  metacarpal  bones. 
7.  Peroneus  longus.  8.  Its  tendon.  9.  Peroneus  brevis.  10.  Its  tendon.  II.  Outer  head  of  gas- 
trocnemius.  12,  12.  Solens.  13.  Tendo  Achillis.  14.  Extensor  brevis  digitorum.  15,  15.  Ab- 
ductor minimi  digiti.  16.  Rectus  femoris.  17.  Vastus  externus.  18.  Its  inferior  fibres.  19. 
Tendon  of  biceps  femoris.  20.  External  lateral  ligament  of  knee.  21.  Tendon  of  popliteus. 


toward  the  elbow.  (3)  A  communicating  branch  to  the  peroneal,  on  the  back  of 
the  tibia,  under  the  flexor  longus  hallucis,  two  inches  above  the  joint.  (4)  In- 
ternal calcanean,  which  communicates  with  the  external  calcanean  branch  of  the 
peroneal  artery  behind  the  tendo  Achillis.  (Fig.  266.)  (5)  Muscular  branches, 
small  and  numerous,  to  the  soleus  and  deep  muscles  on  the  back  of  the  leg. 
(Fig.  266.) 

The  Posterior  Tibial  Canal. — For  practical  purposes  we  may  locate  the 
posterior  tibial  nerve  and  its  accompanying  vessels  in  a  canal,  bounded  as  follows  : 


384  PRACTICAL   ANATOMY. 

Externally,  by  the  flexor  longns  hallucis  ;  internally,  by  the  flexor  longus  digi- 
torum ;  its  floor  is  the  tibialis  posticus,  flexor  longus  digitorum,  tibia,  and  internal 
lateral  ligament ;  its  roof,  the  deep  transverse  fascia,  described  in  a  previous 
paragraph. 

Deep  Muscles  of  the  Leg. — (i)  Popliteus  ;  (2)  flexor  longus  hallucis  ;  (3) 
flexor  longus  digitorum  ;  (4)  tibialis  posticus.  It  is  necessary  now  to  study 
the  posterior  surfaces  of  the  tibia.  (Fig.  208.)  Notice  that  the  oblique  line  of 
the  tibia  has  three  lips  :  (i)  An  upper  one,  occupied  by  the  insertion  of  the  pop- 
liteus  muscle  ;  (2)  a  middle  one,  by  the  soleus  ;  (3)  a  lower  one,  by  two  muscles — 
the  flexor  longus  digitorum  on  the  outer  side  of  the  vertical  line,  and  the  tibialis 
posticus  on  the  inner  side.  Notice,  too,  that  the  posterior  surface  of  the  fibula 
(Fig.  208)  is  occupied  by  the  origin  of  two  muscles  :  the  outer  head  of  the  soleus, 
the  upper  one-third,  and  the  flexor  longus  hallucis,  the  middle  one-third,  of  this 
posterior  surface. 

What  can  be  said  regarding  t/ic  rather  peculiar  origin  and  insertion  of  the  flexor 
longus  digitorum  and  flexor  longus  Jiallucis  f 

They  arise  from  surfaces  of  bone  above,  opposite  their  insertions,  into  the 
phalanges  below  :  The  great  toe  is  on  the  side  opposite  the  fibula ;  the  four 
lesser  toes  are  on  the  side  opposite  the  tibia.  Now,  the  muscle  that  bends  the 
great  toe — flexor  longus  hallucis — arises  from  the  posterior  surface  of  the  fibula, 
middle  one-third  ;  likewise,  the  muscle  that  bends  the  four  lesser  toes — the  flexor 
longus  digitorum — arises  from  the  posterior  surface  of  the  tibia,  middle  one-third. 
To  gain  their  insertions  they  cross  in  the  sole  of  the  foot  in  the  second  layer  ot 
muscles  of  this  region.  (Fig.  270.) 

The  flexor  longus  hallucis  traverses  four  grooves.  (Fig.  268.)  The  flexor 
longus  hallucis  needs  special  mention.  It  passes  through  (i)  a  little  groove  on 
the  posterior  part  of  the  tibia  (Fig.  208) ;  (2)  through  a  pronounced  one  on  the 
narrow  posterior  surface  of  the  astragalus  ;  (3)  through  a  well-marked  groove 
on  the  under  part  of  the  sustentaculum  tali  of  the  os  calcis  (Fig.  268) ; 
(4)  through  a  groove  between  the  two  sesamoid  bones,,  in  the  tendon  of  the 
flexor  brevis  hallucis  at  the  metatarso-phalangeal  articulation.  This  muscle  is 
inserted  into  the  base  of  the  distal  phalanx  of  the  great  toe.  (Fig.  268.) 

Trace  the  popliteus  muscle  to  its  origin.  (Fig.  266.)  Detach  it  at  the  ob- 
lique line  of  the  tibia,  its  insertion,  and  trace  it  between  the  outer  tuberosity  and 
head  of  fibula,  under  the  external  lateral  ligament  of  the  knee  and  the  biceps,  to 
the  outer  side  of  the  external  condyle  of  the  femur. 

Structures  under  Internal  Annular  Ligament. — From  the  internal  malleo- 
lus  to  the  os  calcis  :  (i)  Tendon  of  tibialis  posticus,  next  the  malleolus  ;  (2)  ten- 
don of  flexor  longus  digitorum  ;  (3)  a  sheath  of  connective  tissue  containing  the 
posterior  tibial  nerve  and  artery,  with  a  vein  on  each  side  of  the  artery  ;  (4)  behind 
this  sheath,  and  deeply  buried  in  its  three  upper  grooves,  above  referred  t<>,  is 
the  tendon  of  the  flexor  longus  pollicis.  In  the  dissection  of  the  sole  of  the  foot 
these  several  structures  will  be  traced  to  their  various  destinations. 

The  Peronei  Longus  and  Brevis  ( Figs.  266  and  269). — These  two  muscles 
occupy  almost  the  entire  outer  surface  of  the  fibula.  Commonly,  the  origin  is  as 
follows  :  the  longus  from  the  upper  one-third  and  the  brevis  from  the  middle 
one-third.  (Fig.  207.)  The  muscles  are  separated  in  front  and  behind  from 
adjacent  musculatures  by  intermuscular  septa.  They  pass  under  the  external 
annular  ligament,  immediately  behind  the  malleolus,  and  are  inserted  :  (  f)  the 
brevis  into  the  base  of  the  fifth  metatarsal  (  Fig.  269)  ;  (2)  the  longus  pa>ses 
through  a  groove  on  the  under  surface  of  the  cuboid  bone,  then  through  an 
osseo-aponeurotic  canal,  to  the  base  of  the  first  metatarsal  bone.  (Fig.  275.) 
These  muscles  are  supplied  by  muscular  branches  of  the  nnusculo-cutaneous 
IH.TVC,  a  branch  of  the  external  popliteal.  (Fig.  264.)  These  muscles,  when 


POSTERIOR   PART   OF  LOWER   EXTREMITY. 


385 


acting  together,  assist  the  tibialis  posticus  in  extending  the  ankle.     They  are 
antagonized  by  the  tibialis  anticus  and  peroneus  tertius. 


THE  SOLE  OF  THE  FOOT.     (Fig.  272.) 

The  importance  of  a  knowledge  of  this  region  can  not  be  overestimated. 
The  large  number  of  important  structures  in  a  comparatively  small  area,  com- 
bined with  thick  skin,  dense  plantar  fascia,  and  delicate  lumbrical  muscles,  all  taken 


Origin  of  abductor  minimi  digiti 


Part  of  abductor  minimi  digiti 


Plexor  brevis  minimi  digiti 


Abductor  minimi  digiti 
Lumbricales 


Tendon  of  flexor  brevis 

digitorum 


Flexor  brevis  digitorum 


Abductor  hallucis 


Accessorius 


Flexor  longus  digitorum 


Flexor  lougus  hallucis 
Flexor  brevia  hallucis 

Adductor  hallucis 
Abductor  hallucis 


Tendon  of  flexor  brevif-  digitorum 


FIG.  270. — SECOND  LAYER  OF  THE  MUSCLES  OF  THE  SOLE. 


tog-ether  make   dissection   of  this  area  somewhat  difficult.      A  dissection  of  the 

o 

four  layers  of  muscles  alone  would  be  an  easy  task,  but  here,  as  in  larger  areas 
of  the  body,  nerves  and  vessels  must  be  saved.  The  only  general  rule  I  can  give 
you  is  this  :  Follow  painstakingly  as  a  guide  the  dissections  given  in  the  text, 
and  learn  from  the  figures  what  you  expect  to  find.  Having  done  this,  follow 
each  nerve  and  vessel  out  carefully  to  its  distribution.  No  number  of  written 
pages  will  make  an  awkward  man  improve  his  touch  ;  hence  it  is  impossible  to 


386 


PRA  CT1CAL  ANA  TOM\ '. 


do  more  than  suggest  to  the  student  that  he  should  early  learn  to  cultivate  a 
delicate  touch.  It  requires  but  little  effort  with  the  forceps  to  divide  the  delicate 
connective  tissue  that  surrounds  all  vessels  and  nerves,  and  intervenes  between 
muscles.  In  the  sole  of  the  foot  you  will  find,  in  this  order,  from  without  in- 
ward, the  following  structures  : 

1.  The  thickest  skin  of  the  body — on  the  sole  of  the  foot. 

2.  Superficial  fascia,  very  thick,  containing  granular  fat. 

3.  The  deep  or  plantar  fascia,  with  its  three  divisions. 


Abductor  minimi  digit! 


Flexor  brevis  minimi  digiti 


Tendon  of  flexor  longus  digitorum 


Plexor  brevis  digitorum 


Abductor  liallucis 


Flexor  longus  hallucie 

Flexor  brevis  hallucis 
First  lumbricalis 

—  Tendon  of  adductor  hallucis 


FIG.  271. — FIRST  LAYER  or  mi:  MTSCLES  OF  THE  SOLS, 


4.  The  first  layer  of  muscles:   The  abductor  hallucis,  the  flexor  brevis  digi- 
torum, and  the  abductor  minimi  digiti. 

5.  'I'lic  internal  and  external  plantar  nerves  and  vessels.      (Fig-  272.) 

6.  The  second  layer  of  muscles :  The  tendon  of  flexor  longus  hallucis  and  a 
slip  of  contribution  to  the  flexor  longus  digitorum  ;  tendons  of  the  flexor  longus 
digitorum  ;  the  musculus  accessorius  and  lumbricales  ;  the   nerve-   and    blood- 
supply  to  these  muscles. 

7.  Hie  third  layer  of  muscles :  Flexor  brevis  hallucis  and  its  sesamoid  bones  ; 
abductor  hallucis  muscle  ;  flexor  brevis  minimi  digiti  muscle;  transversus  pedis 
muscle  ;  nerve-  and  blood-sup] >!y  to  these  muscles. 


POSTERIOR   PART   OF  LOWER   EXTREMITY. 


387 


8.  The  fourth  layer  of  muscles:  Dorsal  interossei,  four  in  number;  plantar 
interossei,  three  in  number  ;  the  nerve-  and  blood-supply  to  these.     (Fig.  275.) 

9.  The  tendon  of  tJic  pcroncus  longus  and  its  sesamoid  bone.     (Fig.  275.) 
Incisions. — Start  at  the  middle  of  the  os  calcis  and  make  one  cut  through  the 

skin  to  the  middle  of  the  great  toe  ;    the  other  to  the  middle  of  the  little  toe. 
This  V-incision  will  permit  you  to  find  : 

i.  The  plantar  cutaneous  nerve,  a  branch  of  the  posterior  tibial  nerve. 


Abductor  hallueis 


Flexor  brevis  digitorum 

INTERNAL  PLANTAR 

NER  YE 
Internal  plantar  artery 


BRANCH  OF  INTER- 
NAL PLANTAR 
NERVE  TO  INNER 
SIDE  OF  HALL UX 


Abductor  minimi  digit! 


External  plantar  artery 

EXTERNAL  PLANTAR 

NER  VE 


Ligameuta  vaginales 


DIGITAL  COLLATERAL 
BRANCHES  OF  EX- 
TERNAL PLANTAR 


DIGITAL  COLLATERAL 
BRANCHES  OF  INTER. 
NAL  PLANTAR 


FIG.  272. — SUPERFICIAL  XKKVES  IN  THE  SOLE  OF  THE  FOOT.     (Ellis.) 
(In  this  dissection  the  greater  part  of  the  plantar  fascia  has  been  removed.) 


(Fig.  272.)  This  is  a  sensory  nerve  to  the  heel,  and  you  will  find  it  in  the  thick 
pad  of  fat  in  the  superficial  fascia.  Sometimes  the  granular  fat  here  is  three- 
fourths  of  an  inch  thick. 

2.  The  cutaneous  branches  of  the  internal  and  external  plantar  vessels 
and  nerves.  Exercise  now  your  common  sense  in  removing  the  skin. 

The  superficial  fascia  contains  much  fat.  The  fat  found  in  the  palms  of  the 
hands,  in  the  soles  of  the  feet  of  the  adult,  and  all  over  the  body  of  the  child  at 


88 


PRACTICAL  ANATOMY. 


term,  is  called  granular.  Remove  all  this  fatty  tissue,  and  notice  it  becomes  less 
abundant  in  the  hollow  of  the  foot  and  toward  the  toes. 

The  deep  fascia  occurs  in  the  sole  of  the  foot,  under  two  names  :  (i)  From 
the  heel  to  the  clefts  of  the  toes  it  is  called  plantar  fascia  ;  (2)  from  the  clefts  of 
the  toes  onward  it  forms  very  dense  sheaths  for  the  flexor  tendons  of  the  toes. 
These  sheaths  are  called  the  ligamenta  vaginales  (ligamentum  vaginalis,  in  the 
singular). 

Dissection  of  Plantar  Fascia  and  Ligamenta  Vaginales.  —  Having  now  cut 
through  the  dense,  deep  fascia  of  the  toes,  —  the  ligamenta  vaginales,  —  you 


External  calcanean  artery 
Cutaneous  branch  of  external  plantar 

* 

Abductor  minimi  digit! 

Anastomolic  branch 
External  plantar  artery 


Pint  digital  to  outer  side  of 

lillle,  lot 
Lumbrieal  muscle 

Second  digital 
Third  digital 
Fourth  digital 


Anastomosis  about  inter- 

phalangeal  joint 
Dorsal  branch  of  collateral 
digital 


Anastomosis  of  collateral 
arteries  around  matrix  of  nail 
and  pulp  of  toe 


Internal  calcanean  artery 


Cutaneous  branch  of  internal 
plantar 


Plantar  fascia,  cut 


Abductor  ballucia 


Internal  plantar  artery 


Flexor  brevis  digitorum 


Branch  of  internal  plantar  to 
iliiiilnl  tirfcries  (superficial 
digital] 

Flexor  brevis  hallucis 


Princeps  hallucis,  or  fifth  plantar 
digital  artery 


Collateral  digital  branch  of  princeps 

hallucis  to  second  toe 
Collateral  diiiiinl  branch  »//• 

AofitCdfefO  iinn-r  si<l?  of  ijrrat  toe 
Collateral  digital  branch  nf/irincrps 
hallucis  to  outer  side  of  great  toe 


I  ic.  273.  —  THE  PLANTAR  AKTI  KIK>. 
(From  a  dissection  in  the  Museum  of  St.  Bartholomew's  Hospital.) 


must  find  :  (i)  The  theca  ajid  the  thecal  culs-de-sac,  the  synovial  sheath  of  the 
tendons  ;  (2)  the  vincula,  delicate  thread-like  bands  of  deep  fascia ;  (3)  the  ten- 
dons of  the  flexor  longns  digitorum  ;  (4)  the  tendons  of  the  flexor  brevis  digi- 
torum ;  (5)  the  slits,  in  tendons  of  the  flexor  brevis  digitorum  ;  (6)  the  grooves 
on  the  plantar  surfaces  of  the  pedal  phalanges  ;  (7)  the  outer  division  of  tin- 
plantar  fascia,  quite  thin,  covering  the  abductor  minimi  digiti  muscle  ;  (8)  the  inner 
division  of  the  plantar  fascia,  quite  thin,  covering  the  abductor  hallucis  ;  (9)  the 
middle  division  of  the  plantar  fascia,  very  thick,  strong,  and  glistening,  covering 
the  flexor  brevis  digitorum  ;  (10)  two  intermuscular  grooves  almost  under  tin- 


POSTERIOR    PART   OF  LOU'ER    EXTREMITY.  ?8g 

\J       s 

diverging;  branches  of  the  V-incision  you  made  in  the  skin.  You  will  notice  that 
the  three  divisions  of  the  plantar  fascia  correspond  to  the  three  muscles  in  the 
first  layer,  cover  them,  and  in  great  part  are  almost  inseparably  connected  there- 
with. (Fig.  273.)  The  plantar  fascia  is  part  of  the  origin  of  these  muscles. 
Remove  this  fascia  (Figs.  281  and  273)  and  trace  out  with  the  forceps  the 
branches  of  the  internal  and  external  plantar  nerves  and  vessels.  (Fig.  272.) 

The  plantar  fascia  has  a  central  part  that  covers  the  flexor  brevis  digitorum  ;. 
an  outer  portion  that  covers  the  abductor  minimi  cligiti,  and  is  continuous  with 
the  dorsal  fascia  of  the  foot  externally  ;  an  inner  portion  that  covers  the  abductor 


Part  of  abductor  minimi  cligiti  — 


Flexor  brevis  minimi  digit! 


Trans  versus  pedis 


Divided  tendons  of  flexor  brevis 
digitorum 


Long  plantar  (long  inferior 
calcaneo-cuboid)  ligament 


Flexor  longus  hallucis 
Flexor  longus  digitorum 
Tibialis  posticus 


Flexor  brevis  hallucis 
Adductor  hallucis 


Tendon  of  the  flexor  longus 
hallucis 


Tendon  of  flexor  longus  digitorum 

FIG.  274. — THIRD  LAYER   OF  THE  MUSCLES  OF  THE 


hallucis,  and  is  continuous  internally  with  the  dorsal  fascia  of  the  foot.  Poste- 
riorly, the  plantar  fascia  is  attached  to  the  os  calcts  ;  anteriorly,  it  is  continuous 
with  the  ligamenta  vaginales. 

Muscles  of  the  First  Layer  (Fig.  273). — Dissect  carefully  in  the  grooves 
between  the  middle  muscle  and  the  muscles  on  each  side  of  it.  Trace  all  three 
muscles  back  to  their  origins  on  the  os  calcis.  (Fig.  268.)  Likewise  trace  each 
forward  to  its  insertion  :  the  abductor  liallucis  to  the  base  of  the  first  phalanx 
of  the  great  toe  (Fig.  268)  ;  the  abductor  minimi  digiti  to  the  base  of  the  first 
phalanx  of  the  little  toe  ;  the  flexor  brci'is  digitorum  to  the  second  phalanges 
of  the  four  lesser  toes,  by  cutting  through  the  ligamenta  vaginales  the  long 


390  PRACTICAL  ANATOMY. 

way  of  the  tendon.  (Fig.  268.)  Now  cut  all  three  of  these  muscles  and  turn 
them  forward,  and  expose  the  second  layer  of  muscles.  (Fig.  270.)  Having 
cut  through  the  ligamenta  vaginales  of  the  toes  (Fig.  272),  observe  that  the 
four  tendons  of  the  flexor  longus  digitorum  pass  through  slits  in  the  four 
corresponding  tendons  of  the  flexor  brevis  digitorum,  in  the  same  manner  the 
deep  flexors  of  the  fingers  pass  through  the  superficial  ones. 

Second  Layer  (Fig.  270). — In  the  figure  of  the  flexor  longus  digitorum 
notice  three  accessories:  (i)  The  muscular  acccssorius  (Fig.  268) ;  (2)  the  four 
limibricales  (Fig.  273);  (3)  a  slip  of  contribution  from  the  tendon  of  tlie  flexor 
longus  Iiallueis.  (Fig.  270.)  Having  studied  the  origin  and  insertion  of  these 
muscles,  divide  the  flexor  longus  hallucis  and  flexor  longus  digitorum  near  the 
os  calcis  and  turn  them  all  forward,  as  you  did  the  previous  layer. 

Third  Layer  (Fig.  274). — Trace  out  to  its  origin  each  one  of  the  three  mus- 
cles inserted  into  the  base  of  the  great  toe.  Cut  down  between  the  two  sesamoid 
bones  in  the  tendon  of  the  flexor  brevis  hallucis.  Trace  the  tendon  of  the 
peroneus  longus  across  the  sole  of  the  foot  to  its  insertion  into  the  internal  cunei- 
form and  base  of  great  toe  metatarsal.  (Fig.  275.) 

In  the  fourth  layer  we  have  the  dorsal  interossei  and  the  plantar  interossei. 
In  number  they  are  seven,  four  being  dorsal  and  three  plantar.  In  action  they 
are  analogous  to  the  interossei  of  the  hand.  In  the  foot  they  are  all  supplied 
by  the  external  plantar  nerve ;  in  the  hand  by  the  ulnar  nerve. 

Function  of  the  Interossei  and  Lumbricales. — It  is  comprehensive  to  consider 
the  action  of  these  muscles  in  this  manner  in  the  hand  : 

1.  All  the  interossei  and  lumbricales  acting  together,  flex  at  the  metacarpo- 
phalangeal  articulation  and  extend  at  the  first  and  second  phalangeal   articula- 
tions.    This  gives  about  the  position  for'holding  the  pen. 

2.  The  four  dorsal  interossei  acting  alone,  abduct  the  digits.     Notice  that 
supination   of  the    forearm  is   involuntarily  associated   with   abduction    of  the 
digits. 

3.  The  palmar  interossei  acting  alone,  adduct  the  digits.     Notice  that  prona- 
tion  of  the  forearm  is  associated  involuntarily  with  adduction  of  the  fingers.     In 
the  above  I  have  described  the  action  of  these  muscles  in  the  hand  ;  the  action 
in  the  foot  is  the  same,  only  less  under  control  of  the  will,  since  the  foot  of  man 
is  not  a  prehensile  member. 

4.  The    adductor    line    of  fingers    and    toes.      The    adductor    finger    is    the 
middle  ;  the  adductor  toe  is  the  second.     In  adduction  and  abduction  the  other 
digits  approach  and  recede  from  this  adductor  digit. 

The  Adductor  Digit. — (i)  The  adductor  digit  of  the  hand  has  no  palmar 
interossei  inserted  into  it ;  (2)  the  adductor  digit  of  hand  has  two  dorsal  inter- 
ossei inserted  into  it ;  the  same  is  true  of  the  foot. 

Difference  in  Origin. — Notice  that  the  dorsal  interossei  are  very  large,  and 
arise  from  the  contiguous  sides  of  the  metatarsals  or  metacarpals  ;  that  the 
palmar  are  small,  and  arise  from  one  side  only  of  the  metatarsal  or  metacarpal 
corresponding  to  the  phalanx  into  which  they  are  inserted.  Practise  the 
movements  of  the  lumbricales  and  interossei  on  your  own  fingers  until  you 
master  this  subject  thoroughly. 

Granular  Fat. — Found  in  the  superficial  fascia  of  the  hand  and  foot — palmar 
and  plantar  surfaces — and  in  the  general  supi-rficial  fascia  of  the  f(utus  and  infant. 
Tin-  toughness  of  this  kind  of  fatty  tissue  depends  on  a  largi  r  amount  of  con- 
nective tissue. 

Divisions  of  Plantar  Fascia. — (i)  An  outer  thin  one  that  covers  the  ab- 
ductor minimi  digiti.  (2)  An  inner  one  that  covers  the  abductor  Jiallneis.  (3)  A 
middle  one  that  covers  the  flexor  bre:<is  digitorum.  This  middle  one  is  very 
strong. 


POSTERIOR   PART   OF  LOWER   EXTREMITY.  391 

Ligamenta  Vaginales. — These  are  the  fibrous  sheaths  of  deep  fascia  that 
cover  the  flexor  tendons.  They  are  formed  by  the  deep  fascia,  in  a  modified 
form.  Above,  they  are  continuous  with  the  plantar  fascia.  They  are  attached 
on  the  sides  to  the  margins  of  the  grooves  on  the  plantar  surface  of  the 
phalanges. 

The  Theca  and  Thecal  Culs-de-sac. — The  vaginal  synovial  membrane,  con- 
sisting of  a  visceral  and  a  parietal  layer,  is  called  theca.  The  point  in  conjunction 
between  the  two  layers — about  the  middle  of  the  metatarsal  bones — forms  a  cul- 


Peroneua  longus 


Plantar  interossei 


Dorsal  interossei 


FIG.  275. — FOURTH  LAYER  OF  THE  MUSCLES  OK  THE  SOLE. 


de-sac.  «-Pus  forming  below  in  the  cavity  of  the  tlicca  could  burrow  to  this  point. 
Note  the  difference  in  the  fingers. 

Normally,  the  thecal  cul-de-sac  is  found  as  above  described  in  each  toe,  thus 
making  five  in  number.  The  homologous  structures  of  the  fingers  are  described 
as  three,  the  thumb  and  little  finger  having  none,  since  the  thecal  synovial  mem- 
brane corresponding  to  these  two  members  is  continuous  above  with  the  two 
bursae  under  the  annular  ligament.  My  experience  is,  however,  that  in  the 
majority  of  cases  no  communication  will  be  found  between  the  thecal  sacs  of  the 
thumb  and  little  finger,  and  the  bursse  under  the  anterior  annular  ligament  at 
the  wrist. 

The  Vincula. — These  are  small  silvery  cords  that  extend  from  the  bottom  of 


392  PRACTICAL  ANATOMY. 

the  groove  to  the  tendons,  and  from  tendon  to  tendon,  in  the  ligamenta  vaginales 
of  the  digits  of  the  lower  as  well  as  the  upper  extremity.  By  means  ot  these 
vincula  capillary  vessels  reach  the  synovial  membrane  of  the  tendon. 

The  Internal  Plantar  Nerve. — Begins  under  the  internal  annular  ligament 
at  the  bifurcation  of  the  posterior  tibial  nerve.  It  lies  between  the  first  and  second 
layers  of  muscles  in  the  sole  of  the  foot.  (Fig.  272.)  It  gives  off:  (i)  Articular 
branches  to  the  tarsus  and  metatarsus  and  phalangeal  articulations  ;  (2)  a  cuta- 
neous branch  to  the  skin  of  the  heel  (Fig.  272) ;  (3)  digital  branches  to  the 
inner  three  and  one-half  toes  ;  (4)  muscular  branches  to  the  abductor  hallucis, 
flexor  brevis  hallucis,  flexor  brevis  digitorum,  and  two  lumbricals. 

The  External  Plantar  Nerve. — Begins  at  the  bifurcation  of  the  posterior 
tibial  ;  it  accompanies  the  external  plantar  artery  into  the  sole  of  the  foot.  This 
nerve  is  similar  in  its  distribution  to  the  ulnar  nerve.  It  supplies  a  larger  number 
of  muscles,  still  it  is  smaller  than  the  internal  plantar.  The  muscles  innervated 
by  this  nerve  are:  (i)  All  the  interossei,  seven  in  number,  four  dorsal  and 
three  plantar  ;  (2)  two  lumbricals  on  the  outer  side  ;  (3)  adductor  hallucis  ; 
(4)  the  transversus  pedis.  This  nerve  also  supplies  one  and  one-half  toes — 
the  flexor  accessorius  and  abductor  minimi  digiti. 

The  Internal  Plantar  Artery  (Fig.  273). — This  is  a  small  artery.  It 
begins  with  the  external  plantar  ;  at  the  bifurcation  of  the  posterior  tibial  artery 
under  the  internal  annular  ligament.  It  accompanies  the  internal  plantar  nerve. 

The  External  Plantar  Artery  (Fig.  273). — This  is  the  larger  plantar 
artery.  It  crosses  the  sole  of  the  foot  obliquely  to  the  head  of  the  little  toe  meta- 
tarsal,  lying,  of  course,  in  common  with  all  the  other  plantar  structures,  between 
the  first  and  second  layers  of  muscles  ;  here  it  turns  abruptly  inward  and  forward 
to  the  first  intermetatarsal  space,  where  it  anastomoses  with  the  communicating 
branch  of  the  dorsalis  pedis  artery,  to  complete  the  plantar  arterial  arch. 

The  Plantar  Arterial  Arch. — This  arch  is  formed  between  the  external 
plantar  artery  and  the  dorsalis  pedis.  This  arch  lies  deep -on  the  interossei 
muscles.  It  sends  off  digital  branches  to  the  outer  three  and  one-half  toes. 
At  the  clefts  of  the  toes  these  digital  branches  send  off  perforating  branches, 
which,  passing  up  through  the  interosseous  spaces,  communicate  with  the  meta- 
tarsal  artery  on  the  dorsum  of  the  foot. 

Study  the  origin,  insertion,  and  function  ot  muscles  on  your  dissection,  and 
use  the  tabulated  list  of  muscles  that  each  student  is  expected  to  prepare  for 
himself  for  reference. 

Name  the  muscles  of  the  first  layer  of  the  sole  of  the  foot,  giving  their  origin 
insertion,  nerve-supply  and  blood-supply,  and  action. 

The  Abductor  Hallucis. — Origin,  from  the  plantar  fascia  ;  greater  tuberosity  o 
os  calcis  ;  intermuscular  fascia  between  itself  and  the  flexor  brevis  digitorum. 
Insertion,  under  surface  of  base  of  first  phalanx  of  the  great  toe.  This  muscle 
abducts  and  flexes  the  great  toe.  Nerve-supply,  the  internal  plantar  nerve. 

The  Abductor  Minimi  Digiti. — Origin,  plantar  fascia  ;  lesser  tuberosity  of  the 
os  calcis  ;  the  intermuscular  septum  between  itself  and  the  flexor  brevis  digi- 
torum ;  the  long  plantar  ligament.  Insertion,  under  surface  of  base  of  first  phalanx 
of  little  toe.  This  muscle  abducts  the  little  toe  from  the  mid-line.  Nerve-supply, 
the  external  plantar. 

The  Flexor  Brci v\  Digitornin.-  Origin,  the  plantar  fascia  ;  the  greater  tuber- 
osity of  the  os  calcis  ;  the  lateral  intermuscular  fascia.  Insertion,  into  the  sides 
of  the  middle  phalanges.  These  tendons  are  perforated  by  the  tendons  of  the 
flexor  longus  digitorum.  Nerve-supply,  the  internal  plantar. 

Name  the  muscles  of  the  second  layer  of  the  sole  of  ike  foot,  giving  origin,  inser- 
tion, function,  and  ncn'c-snpply. 

Tlic  Mnscnliis  Accessorius. — Origin,  tin-  concave  inner  surface  of  the  os  calcis 


POSTERIOR   PART   OF  LOWER   EXTREMITY.  393 

the  under  surface  of  the  os  calcis  ;  the  long  plantar  ligament.  Insertion,  the 
upper  surface  and  outer  oblique  border  of  the  flexor  longus  digitorum.  Demon- 
strate carefully  on  your  dissection  the  specific  double  origin  and  double  insertion 
of  this  muscle.  To  do  this,  hold  the  heel  firmly  and  extend  the  toes  vigorously. 
Nerve-supply,  the  external  plantar,  a  branch  of  the  posterior  tibial. 

The  lumbrical  muscles  are  four  in  number.  They  arise  in  connection  with  the 
tendons  of  the  flexor  longus  digitorum,  as  follows  :  The  first  from  the  great-toe 
side  of  the  first  tendon,  beginning  at  the  point  where  this  tendon  leaves  the  main 
tendon  of  the  muscle.  The  other  three  arise  from  the  adjacent  tendon,  as  seen  in 
figure  270.  Insertion,  into  the  inner  border  of  the  expanded  tendons  of  the  ex- 
tensor communis  digitorum.  The  nerve-supply  is  from  the  external  plantar  for 
the  two  outer  ;  the  internal  plantar  for  the  two  inner.  Acting  with  the  interossei, 
these  muscles  flex  the  metatarso-phalangeal  articulation  and  extend  the  first  and 
second  interphalangeal  joints.  Note,  then,  the  homology,  both  in  nerve-supply 
and  function,  of  these  muscles  and  the  lumbricales  manus. 

The  intimate  association  of  the  accessorius  and  lumbricales  pedis  with  the 
flexor  longus  pollicis  and  flexor  longus  digitorum  justifies  some  authors  in  classi- 
fying these  latter  also  in  the  second  group.  For  details  of  these  muscles,  which 
are  not  here  considered  as  belonging  to  the  second,  the  reader  is  referred  to 
page  389. 

Name  tJic  muscles  of  the  third  layer  of  tJu\  sole  of  tJic  foot,  giving  origin,  inser- 
tion, function,  and  nerve-supply. 

The  Flexor  Brevis  Hallucis. — Origin,  from  the  under  surface  of  the  cuboid 
bone  ;  the  long  plantar  ligaments  ;  the  expansion  of  the  tibialis  posticus  in  the 
middle  of  the  sole  of  the  foot.  Insertion,  base  of  the  first  phalanx  of  the  great 
toe,  both  on  the  inner  and  outer  borders.  (Fig.  268.)  The  tendon  of  the  flexor 
longus  hallucis  passes  between  the  two  parts  of  the  muscle,  playing  over  a  pulley 
formed  by  the  two  sesamoid  bones  developed  in  the  tendon  of  flexor  brevis  hal- 
lucis. (Fig.  274.)  This  muscle  flexes  and  slightly  adducts  the  first  phalanx. 

The  Adductor  Hallucis  (Fig.  274). — Origin,  the  sheath  of  the  peroneus  longus 
formed  by  the  long  plantar  ligament  ;  the  under  surface  of  the  second,  third,  and 
fourth  metatarsals.  Insertion,  into  the  outer  part  of  the  base  of  the  first  phalanx 
of  the  great  toe.  Nerve-supply,  the  external  plantar. 

The  Transversus  Pedis  (Fig.  274). — Origin,  the  deep  transverse  metatarsal 
ligaments  and  the  plantar  ligaments  of  the  three  outer  metatarso-phalangeal 
articulations.  Insertion,  into  the  base  of  the  first  phalanx  of  great  toe  on  the 
outer  side.  Nerve-supply,  the  external  plantar.  Action,  to  adduct  the  great  toe. 

The  Flexor  Brevis  Minimi  Digiti. — Origin,  base  of  fifth  metatarsal  bone,  under 
surface  (Fig.  268);  sheath  of  peroneus  longus.  (Fig.  274.)  Insertion,  into  the 
under  surface  of  base  of  first  phalanx  of  the  little  toe.  Action,  to  flex  the  little 
toe.  Nerve-supply,  the  external  plantar. 

The  interossei  have  been  fully  considered.  The  student  is  urged  to  study 
carefully  the  action  of  these  muscles,  both  separately  and  in  conjunction  with  the 
lumbricales. 


26 


THE  BACK. 


Dissection. — Dissection  of  the  back  is  often  almost  wholly  ignored ;  and  why 
ignored?  I  would  ask.  Simply  because  (i)  it  is  considered  as  belonging  to  a 
region  of  the  body  called  not  practical ;  because  (2)  its  structures  are  somewhat 
difficult  to  expose  on  dissection.  Says  one  :  "There  are  only  two  incisions  in  the 
whole  category  of  diseases  of  this  region — (i)  for  renal  operations  ;  (2)  for  car- 
buncles. Why,  then,  should  one  learn  to  dissect  seven  layers  of  muscles?"  I 
would  answer,  "  If  the  former  incision  is  made  in  the  proper  place,  and  the  latter 
deep  enough,  these  alone  are  enough  to  justify  careful  study  and  dissection  of  this 
area."  I  desire  to  accentuate  the  following  : 

1.  The  thick  superficial  fascia,  and  its  very  dense  connective -tissue  frame- 
work, since  this  is  a  favorite  locality  for  boils  and  carbuncles,  offering  greater 
resistance  to  pus  than  do  all  the  other  structures  combined,  bet\\een  this  and  the 
suboccipital  triangle.     (Law  of  projectiles.) 

2.  The  erector  spinae  and  the  quadratus  lumborum,  since  these  muscles 
are  guides  to  lumbar  colotomy  and  lumbar  nephrectomy  and  nephrotomy. 

3.  The  last  rib,  since  in  the  above  operations,  nephrectomy  and  nephrotomy, 
the  pleura  must  not  be  cut  or  wounded,  and  the  last  rib  is  the  guide. 

4.  The  complexus  muscle,  since  this  forms  the  roof  of  the  suboccipital  tri- 
angle.    On   the  floor  of  the  triangle  are  the  vertebral  artery  and   suboccipital 
nerve  ;  crossing  the  triangle,  immediately  under  the  complexus  muscle,  is  the 
great  occipital  nerve. 

5.  The  vertebral  aponeurosis,  since  this  separates  the  muscles  which  act 
upon  the  shoulder  girdle — the  first  and  second  layers — from  the  proper  muscles 
of  the  back — viz.,  those  that  move  the  vertebral  column  by  acting  on  the  spinous 
and  transverse  processes  and  the  parts  of  the  skull  serially  continuous  therewith. 

6.  The  erector  Spinae,  since  this  is  the  location  of  lumbago,  the    so-called 
muscular  rlicumatism  of  the  back.      I   wish  you  to  note  particularly  in  this  con- 
nection the  anatomical  reasons  why  the   pain  of  lumbago  need  not  be  mistaken 
for  pain  in  diseases  of  the  kidneys  and  surrounding  viscera,  of  the  rectum,  and  of 
the  uterus.      The  pain  in  lumbago  (in  any  of  the  proper  muscles  of  the  back)  is 
logically  located  in  the  small  of  the  back,  because  these  muscles  are  supplied  by 
somatic    nerves.      It  could   not  be   mistaken  for  the-  above  pains,  because  those 
organs — uterus,  kidney,  rectum — have  a  sympathetic  nerve-supply,  and  this  pain 
is  reflected  in   the   distribution   of  the  anterior  primary  divisions   of  the   somatic 
nerves;   the    proper  muscles    of  the  back  are  supplied  by  the  posterior  primary 
divisions  of  tin-  spinal  nerves,  and  these  latter  have-  no  sympathetic  connections. 
(See    l-'imdamental    Principle's  of   Anatomy:   Application  of    Law   of  Projectiles 
in  Cases  of  Pain  Remote  from  Place  of  Injury.)  « 

394 


THE   BACK. 


395 


MUSCLES  OF  THE  BACK,  GROUPED  ACCORDING  TO  LAYERS,  AND  THEIR  NERVE-SUPPLY. 


First  layer,  .    . 
Second  layer,  . 

Third  layer,    . 
Fourth  layer,  . 

K 

c 

t/i 
Fifth  layer,  .   >_ 

o 
G 

W 

Sixth  layer,  .    . 
Seventh  laver, 


Trapezius.     Nerve-supply,  spinal  accessory,  cervical  plexus. 

Levator  anguli  scapulae.     Nerve-supply,  cervical  plexus. 

Rhomboideus  minor.     Nerve-supply,  brachial  plexus. 

Rhomboideus  major.     Nerve-supply,  brachial  plexus. 

Latissimus  dorsi.     Nerve-supply,  the  long  subscapular. 

Serratus  posticus  superior.  1    Nerve-supply,  posterior  divisions  of  spinals, 

Serratus  posticus  inferior,     j        external  branches. 

Splenius  capitis.  )    Nerve-supply,  posterior  divisions  of  spinals,  external 

Splenius  colli.       }       branches. 

Outer  division  (nerve-supply,  all  by  posterior  divisions,  spinal  nerves)  : 

1.  Ileo-costalis. 

2.  Musculus  accessorius  ad  ileo-costalem. 

3.  Musculus  cervicalis  ascendens. 

Middle  division  (nerve-supply,  posterior  divisions  of  spinals) : 

1.  Musculus  longissimus  dorsi. 

2.  Musculus  transversalis  colli. 

3.  Musculus  trachelo-mastoideus. 

Inner  division  (nerve-supply,  posterior  divisions  of  spinals) : 

Musculus  spinalis  dorsi. 
Musculus  complexus.     Nerve-supply,  suboccipital,  great  occipital,  posterior 

division. 

Semispinalis  colli.     Nerve-supply,  posterior  divisions  of  spinal. 
Semispinalis  dorsi.     Nerve-supply,  posterior  divisions  of  spinal. 
Rotatores  spinae.     Nerve-supply,  posterior  divisions  of  spinal. 
Multifidus  spinae.     Nerve-supply,  posterior  divisions  of  spinal. 

Interspinales.     Nerve-supply,  posterior  divisions  of  spinal. 
Intertransversales.     Nerve-supply,  posterior  divisions  of  spinal. 


Occipital  Group  (nerve-supply,  suboccipital  nerve). — Rectus  capitis  posticus 
minor,  rectus  capitis  posticus  major,  rectus  capitis  lateralis,  obliquus  superior, 
obliquus  inferior.  Nerve-supply,  great  occipital  and  suboccipital  nerves. 


ANALYSIS    OF    THE    SIMPLE    MOVEMENTS    OE    THE    SPINAL 
COLUMN  AND  THE  MUSCLES  WHICH  PRODUCE  THEM. 

View  the  skeleton  from  behind,  and  note  the  juxtaposition  of  spines,  laminae, 
transverse  processes,  articular  processes,  and  bodies  or  centra  of  vertebrae.  Note 
the  head  of  the  rib  articulating  with  the  body,  and  the  tubercle  of  the  rib  articulat- 
ing with  the  transverse  process  of  a  vertebra.  (Fig.  276.)  Each  is  a  movable 
articulation,  because  it  has  a  synovial  sac.  Note  the  central  pulpy  nature  of  the 
intervertebral  disc.  Note  the  manner  in  which  the  head  of  the  rib  articulates 
with  two  bodies  and  the  cartilaginous  disc,  and  recall  the  exceptions  to  this  rule 
in  the  first,  ninth,  tenth,  eleventh,  and  twelfth  thoracic  vertebrae.  (Fig.  277.) 


SIMPLE  MOVEMENTS  OF  THE  SPINE. 

1.  Lateral  flexion  of  the  column  by  the  intertransversales. 

2.  Extension  of  the  column  by  the  interspinalcs  and  spinalis  dorsi. 

3.  Lateral  rotation  by  the  rotatores  spinae,  extending  from  the  transverse  pro- 
cess of  the  vertebra  below  to  the  lamina  of  the  bone  above. 

4.  Extension  and  lateral  rotation  of  the  column  by  the  multifidus  spinae,  in  a 
typical  region  extending  from  the  transverse  processes  of  the  vertebrae  below,  to 
the   lower    border    of  the  spines  above,  from  the    last  lumbar  to    the    second 
cervical  vertebrae. 

Note  that   extension   and   lateral   rotation  are  the  two  most  common  move- 


396 


PRACTICAL  ANA  TOM}. 


merits  of  the  human  vertebral  column  ;  that  there  are  three  regions  where  this 
movement  is  specially  pronounced:  (i)  the  tlioracic  region;  (2)  the  ccrrical 
region  ;  (3)  the  region  between  the  head  and  neck. 


Anterior  costo-central 
or  stellate  ligament 


Costo-central  synovial 
sac 


Laminar  portion  of  inter- 
vertebral  disc 


Central  pulpy  portion  of  inter- 
vertebral  disc 


Middle  costo-trana- 
verse  ligament 


Costo-transverse  synovial  sac 


Posterior  costo-transverse 
ligament 


FIG.  276. — HORIZONTAL  SECTION  THROUGH  THE  INTERVKRTEURAL  Disc  AND  RIBS. 


The  interartioular 
ligament 


The  superior  or  anterior 
costo-transverse  ligament! 


The  stellate  ligament 


FIG.  277. — SIIOWIM;   THE   ANTERIOR   COMMON    LICAMI.M    <>i    mi     MMNE,  AND  mi    (  > >.\ SECTION 

OF   THE    RlBS    WITH     1111      \KRTEBR>E. 


The  semispinalis  dorsi,  semispinalis  colli,  and  complexus  are  accessory 
to  the  multifulus  spin;r. 

Note  the  means  to  an  end,  then,  in  (i)  the  semispinalis  dorsi  (Fig.  285)  ex- 
tending from  transverse  processes  to  the  spines  in  such  a  manner  as  to  strengthen 
the  dorso-rervical  junction.  The  scinispinalis  colli  is  likewise  disposed  to 


THE    BACK. 


397 


strengthen  the  same  region.  So  we  will  see  that  from  the  transverse  processes 
of  all  the  dorsal  vertebrae  to  the  spines  of  all  the  dorsals  and  cervicals  there 
is  a  continuous,  uninterrupted  plane  of  oblique  muscular  fibres.  (Fig.  285.) 
They  are  called  semispinales  dorsi  and  colli.  They  are  synergistic  physiologi- 
cally to  the  multifidus  spinae — only  a  larger  edition  of  the  same.  Their  function 
is  extension  and  lateral  rotation. 

Note,  again,  there  is  an  upward  continuation  of  this  same  muscular  arrange- 
ment to  the  head — the  complexus,  a  semispinalis  capitis.  (Fig.  283.)  It  arises 
from  the  transverse  processes  of  the  upper  six  thoracic  and  last  cervical,  and  is 


Trapezius 


INION  OR  EXTERNAL-OCCIPITAL  PROTUBERANCE 


SUPERIOR  NUCHAL  LINE 

Occipito-frovitalia 

MIDDLE  NUCHAL  LINE 
Sterno-mastoid 

SpleniuB  capitis 

Eectus  cap.  post.  min. 
Rectus  cap.  post.  maj. 

Superior  oblique 

INFERIOR  NUCHAL  LINE 


Eectus  capitis  lateralis 


POSTERIOR  CONDYLOID 
FORAMEN 


JUGULAR  PROCESS 


BASI-OCCIPITAL 


FIG.  278. — THE  OCCIPITAL.     (External  view.) 


inserted  into  the  occipital  bone.     Its  action  is  extension  and  lateral  rotation   of 
the  head. 

The  above  are  the  simple  movements  of  the  vertebral  column.  Complex 
movements  may  be  had  by  combination  of  different  simple  movements.  I  have 
spoken  of  the  mechanism  in  advance  of  the  dissection,  to  inspire  the  student  to 
greater  care  in  his  work. 


NERVES  THAT  SUPPLY  THE  BACK. 

1.  Tlie  long  subscapnlar  nerve  to  the  latissimus  dorsi  (brachial  plexus). 

2.  The  spinal  accessory  nerve  to  the  trapezius  (twelfth  cranial  nerve). 

3.  T/ie  snboccipital  nerve  to  the  complexus,  recti,  and  oblique  muscles. 

4.  Muscular  branches  from  the  cervical  plexus  to  the  rhomboids  and  levator 
anguli  scapulae. 

5.  Posterior  divisions  of  the  spinal  nerves,  thirty-one  pairs  to  other  muscles. 

6.  The  great  occipital  nerve,  to  the  complexus  muscle  and  to  the  scalp. 
Scheme  for  the  Posterior  Divisions  of  the  Spinals. — All  except  the  first 

cervical    divide  into  internal  and  external  branches  ;  the  internal  branches  sup- 
ply the   sixth  and  seventh   layers,  the  external  branches  the  remainder  ;  they 


398  PRACTICAL   ANATOMY. 

all  supply  the  skin  of  the  back  ;  there  are  twelve  dorsal  cutaneous  nerves  ;  the 
suboccipital  is  the  first  cervical  posterior  division  ;  the  great  occipital  is  the 
posterior  division  of  the  second  cervical  ;  the  third  occipital  is  a  branch  of  the 
third  cervical,  posterior  division. 

You  will  find  the  (i)  suboccipital  nerve  in  the  suboccipital  triangle  ;  (2)  the 
great  occipital  under  the  complexus   muscle  crossing  the  suboccipital    triangle  ; 

(3)  the  spinal  accessory  nerve  between  the  trapezius  and  sterno-mastoid  muscles  ; 

(4)  the  third  occipital  internal  to  the  great  occipital ;  (5)  the  suboccipital  emerges 
between  the  occipital  bone  and  atlas  behind  the  vertebral  artery  ;    (6)  the  great 
occipital  nerve  emerges  between  the  atlas  and  axis  and  passes  under  cover  of  the 
complexus  muscle  through  the  lower  and  inner  part  of  the  suboccipital  triangle  ; 
(7)  the  great  occipital  nerve  joins   the  occipital   artery  under  the  trapezius  and 
lies  on  the  complexus  muscle  ;  (8)  other  posterior  divisions  emerge  between  the 
transverse  processes. 


Arteries  of  the  back  are:  (i)  the  dorsal  branches  of  all  the  intercostals  ; 
(2)  the  deep  cervical,  a  branch  of  the  superior  intercostal  ;  (3)  the  arteria  prin- 
ceps  cervicis,  a  branch  of  the  occipital  ;  (4)  these  arteries,  represented  by  num- 
bers 2  and  3,  anastomose  under  the  complexus. 

The  student  who  studies  in  advance  of  his  dissection  the  foregoing  pages 
will  have  no  difficulty  in  making  a  thorough  dissection  of  the  back. 

Dissection. — Locate  :  (i)  The  spinous  processes  of  the  vertebra  in  the  dorsal 
and  lumbar  regions  ;  (2)  the  iliac  crest ;  (3)  the  crest  of  the  scapular  spine  ;  (4) 
the  three  lips  of  the  crest  of  the  scapular  spine  ;  (5)  the  acromion  process  of  the 
scapula ;  (6)  the  external  occipital  protuberance ;  (7)  the  vertebra  proinincns  ; 
(8)  the  angles  of  the  ribs,  and  note  the  distance  they  are  from  the  spinous 
processes;  (9)  the  iliac  junction  with  the  sacrum  ;  (10)  the  rudimentary  sacral 
spines ;  (i  i)  the  ma stoid processes ;  (12)  the  clavicle ;  (13)  the  twelfth  rib. 

Incisions. — (i)  From  external  occipital  protuberance  to  the  rudimentary 
sacral  spines  ;  (2)  from  one  acromion  process  of  the  scapula  to  the  other.  Begin 
to  remove  the  skin  at  the  intersectional  point  of  the  vertical  and  horizontal  inci- 
sions just  made. 

Observe  the  cutaneous  nerves  piercing  the  trapezius  and  latissimus  dorsi,  on 
removing  the  skin.  These  are  the  cutaneous  branches  of  the  posterior  divisions 
of  the  spinal  nerves.  (Fig.  279.) 

Note  the  very  heavy  variety  of  the  superficial  fascia.  This,  you  will 
observe,  is  tightly  bound  to  the  deep  fascia  by  fibrous  trabeculaj  that  make 
removal  of  the  skin  difficult.  This  fascia,  especially  in  the  region  of  the  neck, 
is  a  common  place  for  boils  and  carbuncles.  Observe  the  great  depth  you  will 
have  to  cut  to  get  through  this  fascia. 

Clean  all  the  superficial  fascia  off  and  make  your  work  look  like  figure  22~ . 
Here  you  have  exposed  two  muscles  :  (i)  The  trapo/ius  ;  (2)  the  latissimus  dorsi. 

The  Trapezius. — Trace  its  origin  to  the  external  occipital  protuberance,  the 
inner  third  of  the  superior  nuchal  line,  the  ligamentum  nuclijc,  the  seventh  cer- 
vical spine,  and  all  the  dorsal  spines.  Now  pull  the  arm  outward  (Fig.  280),  and 
put  the  muscle  on  the  stretch.  Study  its  descending  fibres  to  the  outer  third  of 
the  clavicle  and  acromion  ;  its  ascending  and  horizontal  ones  to  the  upper  lip  of 
tin-  spine  of  the  scapula. 

Develop  the  lower  margin  of  the  trape/.ius  muscle,  and  observe  that  it  overlaps 
the  latissimus  dorsi.  Find  the  space  between  the  trapezius  and  sterno-cleido-mas- 
toid  muscle.  Locate  in  this  space  the  spinal  accessory  nerve,  and  trace  the 


THE   BACK. 


399 


same  to  the  trapezius.      Also  trace  the  nerve  upward  to  where  it  comes  through 
the  sterno-cleido-mastoid  muscle. 

Latissimus  Dorsi. — Trace  the  origin  to  the  six  lower  thoracic  spines,  lum- 


Semi-apinalis 


Multifldus  spinae 


LongissimuB 
dorai 


Ilio-oostalia 


Rhomboideua 
major 


Latiaaimua 
dorsi 


Gluteus 
maximus 


FIG.  279. — DISTRIBUTION  OF  THE  POSTERIOR  PRIMARY  DIVISIONS  OK  THE  SHXAI. 

NERVES.     (Henle.) 


bar  aponeurosis,  and  iliac  crest,  posterior  one-third  ot  outer  lip.  Develop  the 
upper  border  and  expose  the  infraspinatus  and  teres  major  in  the  triangle  formed  by 
this  muscle,  the  deltoid,  and  the  trapezius.  (Fig.  280.)  Develop  with  the  scissors 
the  lower  border  of  the  muscle.  The  latissimus  dorsi  will  be  inserted  into  the  poste- 


400  PRACTICAL   ANATOMY. 

nor  lip  ofthe  bicipital  groove  of  the  humerus  with  the  major  tereal  muscle.  These 
two  muscles,  the  trapezius  and  the  latissimus  dorsi,  may  now  be  removed  by  cut- 
ting through  their  origins,  tracing  the  same  carefully  to  their  respective  inser- 
tions, where  they  may  be  detached,  when  you  will  have  exposed  (Fig.  281) : 

1.  The  musculus  levator  anguli  scapulae. 

2.  The  musculus  rhomboideus  minor. 

3.  The  musculus  rhomboideus  major. 

4.  The  musculus  splenius  capitis. 

5.  The  musculus  complexus. 

6.  The  musculus  serratus  posticus  inferior  and  superior. 

7.  Vertebral  aponeurosis. 

8.  The  occipital  artery  on  the  complexus  muscle. 

9.  The  great  occipital  nerve. 

Now  develop  with  scissors  the  four  serrations  of  insertion  into  the  lower  four 
ribs  of  the  serratus  posticus  inferior.  This  muscle  arises  from  the  spines  of  the 
eleventh  and  twelfth  thoracic,  and  the  first  and  second  dorsal  vertebrae.  Pull 
the  arm  outward,  and  put  the  rhomboids  on  the  stretch.  Study  their  insertion 
into  the  middle  lip  of  the  vertebral  border  of  the  scapula.  Develop  their 
spinous  origin.  (Fig.  -281.) 

Cut  the  rhomboids  near  their  origins  and  turn  them  outward.  (Fig.  281.) 
See  the  nerve-supply  on  the  under  surface  near  the  centre.  See  also  the  pos- 
terior scapular  artery,  a  continuation  of  the  transversalis  colli  artery. 

The  rhomboideus  minor  (Fig.  281)  arises  from  the  spine  of  the  seventh 
cervical  and  first  thoracic  vertebrae,  and  from  the  ligamentum  nuchae.  It  is 
inserted  into  the  vertebral  border  of  the  scapula  opposite  the  spine.  Its  nerve- 
supply  is  from  the  brachial  plexus. 

The  rhomboideus  major  (Fig.  281)  arises  from  the  five  upper  thoracic  ver- 
tebrae and  their  supraspinous  ligament,  and  is  inserted  into  the  middle  lip  of  the 
vertebral  border  of  the  scapula  from  a  point  opposite  the  spine  above  to  the  in- 
ferior angle  below.  The  nerve-supply  is  from  the  brachial  plexus.  The  action 
of  the  rhomboids  is  to  lift  the  scapula  upward,  backward,  and  inward. 

Levator  Anguli  Scapulae  (Fig.  281). — Pull  the  arm  outward  and  find  the  in- 
sertion of  this  muscle  into  the  middle  lip  of  the  vertebral  border  of  the  scapula 
above  the  spine.  Trace  its  three  or  four  tendons  of  origin  to  the  anterior  tubercles 
of  the  transverse  processes  of  the  four  upper  cervical  vertebrae.  This  muscle  deri\  is 
its  nerve-supply  from  the  cervical  plexus.  Its  action  is  to  elevate  the  scapula 
and.  by  producing  rotation  of  the  same,  it  depresses  the  point  of  the  scapula. 

Serratus  Posticus  Superior  (descending  fibres)  (Fig.  282). — This  muscle 
lies  under  the  levator  anguli  scapulae  and  rhomboids.  It  arises  by  aponeurosis 
from  the  seventh  cervical  spine  and  the  upper  three  dorsal  spines.  It  is  inserted 
into  the  second,  third,  fourth,  and  fifth  ribs,  a  little  beyond  the  angle.  The 
nerve-supply  is  from  the  posterior  primary  divisions  of  the  second  and  third 
intercostals. 

The  serratus  posticus  inferior  (ascending  fibres)  (Fig.  282)  arises,  by 
aponeurosis,  from  the  two  lower  dorsal  and  three  upper  lumbar  spines;  it  is 
inserted  into  the  four  lower  ribs  a  little  beyond  the  angle.  Notice  the  difference 
between  the  two  serrati  museles.  The  upper  is  inserted  into  the  upper  border, 
the  lower  into  the  lower  border  of  ribs. 

The  Vertebral  Aponeurosis  (Fig.  2X2). — Internally  you  see  this  aponeurosis 
alt. idled  to  the  spines  ;  externally  it  is  attached  to  the  angles  of  the  ribs  ;  below 
it  blends  with  the  serratus  postieus  inferior  and  latissimus  dorsi  ;  above  it  passes 
behind  the  superior  serratus.  It  separate's  the  proper  muscles  of  the  back  from 
those  that  act  on  the  shoulder  girdle. 

The  Splenius  Capitis  and  Colli. —  Develop  the  long,  pointed  origin  of  this 


THE   BACK. 


401 


Triceps 


Teres  minor 
Ini'raspinatus 

Teres  major 

Bhotnboideus  major 

Pectoralis  major 


Obliquus  externus 


Gluteus  mediu 


Gluteus  maximus 


FIG.  280. — FIRST  LAYER  OF  MUSCLES  OF  THE  HACK. 


402 


PRACTICAL    ANATOMY. 


muscle  from  the  sides  of  the  spines  of  the  seventh  cervical  and  six  upper  dorsal 
vertebne.      (Fig.   281.)     The  muscle  has  two  insertions:  (i)  into  the  mastoid 


Supraapinatus 


Obliquua  interims 


Complexua 
Splenius  oapitii 


Levator  anguli  scapulae 


Serratua  posticus 
superior 


Rhomboideus  minor 


Spleniua  colli 
Rhomboideua  major 


281.— 'I'm    l.i  \  \iou   AM. ri. i  SCAPULA  AM>  RHOMBOIDEI. 

process  of  the  temporal  bone  ;  (2)  into  the  posterior  tubercles  of  the  transverse- 
processes  of  the  three  upper  cervical  vertebrae.  The  nerve-supply  is  from  the 
posterior  primary  divisions  of  the  cervical  nerves. 


THE   BACK. 


4°3 


Erector  Spinae  and   Branches. — Remove  the  vertebral   aponeurosis  (Fig. 
282)  and  expose  the  fifth  layer  of  muscles  and  its  subdivisions.      (Fig.  283.) 


Complexus 


Splenius  capitia 


Splenius  colli 


Serratus  postieus  superior 


Vertebral  aponeurosis 


Serratus  postieus 
inferior 


Obliquus  interims 


Origin  of  latissimus 
dorsi 


SEVENTH  CERVICAL  VERTEBRA 


TWELFTH  THORACIC  VERTEBRA 


FIFTH  LUMBAR  VERTEBRA 


FIG.  282. — THE  THIRD  AND  FOURTH  LAYERS  OF  THE  MUSCLES  OF  THE  HACK. 


Origin. — (i)  The  spines  of  the  two  last  thoracic,  all  the  lumbar,  and  the  four 
upper  sacral   vertebrae  ;    (2)   the  back   of  the   side  portion  of  the  fourth  sacral 


404 


PR  A  CTICAL  ANA  TOMY. 


vertebra;    (3)   the   posterior   sacro-iliac   ligament,   a  few  of   these    fibres    being 
continuous  with  the  origin  of  the  gluteus  maximus  ;    (4)  the   upper  part  of  the 


ComplexuB 
Trachelo-mastoid 


Traneversalis  colli 


Longissimuo  dorsi 


Accessor-jus  ad  ilio- 
ooatalein 


Spinalis  dorsi 


Ilio-costalis 


Obliquus  internus 


Erector  epinae 


SEVENTH  CERVICAL  VERTEBRA 


TWELFTH  THORACIO  VERTEBRA 


FIFTH  LUMBAR  VERTEBRA 


IMC;.   283. — Tin.  KII-TII    I.AYKK  OF  TDK  Mfsci.Es  UK   run  HACK. 

posterior  superior  spine  of  the  ilium,  and  the  posterior  fifth  of  the  iliac  ere.1 

(Morris). 


THE   BACK.  405 

Insertion. — It  is  continuous  abovre  with  the  spinalis  dorsi,  longissimus  dorsi, 
and  ilio-costalis. 

Locate  the  spinalis  dorsi  first,  the  inner  insertion  of  the  erector  spinae 
muscle.  Remember  it  takes  its  origin  from  the  inner  part  of  the  erector  spinae. 
Trace  its  tendons  of  insertion  to  the  spines  of  the  upper  thoracic  vertebrae. 

Locate  the  groove  between  the  outer  and  middle  divisions  of  the  erector 
spinae.  In  this  groove  you  will  find  the  external  branches  of  the  posterior 
divisions  of  the  spinal  nerves,  in  company  with  the  dorsal  branches  of  the  inter- 
costal vessels.  Turn  the  muscles  apart,  as  in  figure  284. 

The  outer  division  of  the  erector  spinae  is  called  ilio-COStalis,  to  its  insertion 
into  the  angles  of  the  lower  ribs,  from  the  sixth  to  the  eleventh  rib.  It  is  continued 
upward  through  the  back  and  neck  as  (i)  the  accessorius,  (2)  cervicalis  ascendens. 

Accessorius  ad  ilio-costalem  arises  from  the  angles  of  the  ribs,  seventh  to 
eleventh,  and  is  inserted  into  the  angles  of  the  ribs  from  the  second  to  the  fifth, 
and  into  the  transverse  process  of  the  seventh  cervical  vertebra. 

Cervicalis  ascendens  arises  from  the  ribs — fourth  to  fifth  upper — internal  to 
the  costal  insertion  of  the  accessorius,  and  is  inserted  into  the  posterior  tubercles 
of  the  fourth,  fifth,  and  sixth  cervical  transverse  processes. 

The  middle  division  of  the  erector  spinae  continues  through  the  thorax  under 
the  name  of  longissimus  dorsi ;  through  the  neck,  to  the  head,  as  the  trans- 
versalis  colli  and  trachelo-mastoid.  (Fig.  284.) 

The  longissimus  dorsi  arises:  (i)  From  the  middle  part  of  the  erector 
spinae  ;  (2)  from  the  transverse  processes  of  some  of  the  lower  thoracic  vertebras. 
It  is  inserted  into  :  (i)  The  ribs  external  to  their  tubercles  ;  (2)  the  transverse 
processes  of  the  thoracic  vertebras  ;  (3)  into  the  accessory  tubercles  of  the  upper 
lumbar  and  lower  thoracic  vertebrae ;  (4)  into  the  transverse  processes  of  the 
upper  lumbar  vertebrae. 

Transversalis  colli  arises  from  the  transverse  processes  of  the  upper  six 
thoracic  vertebrae,  internal  to  the  insertion  of  the  longissimus  dorsi.  It  is  in- 
serted into  the  posterior  tubercles  of  the  transverse  processes  of  the  vertebrae  from 
the  second  to  the  sixth  cervical  vertebrae  inclusive. 

The  trachelo-mastoid  (Fig.  284)  is  the  inner  part  of  the  transversalis  colli 
continued  in  the  mastoid  process.  In  some  cases  this  muscle  is  unusually  well 
developed. 

The  sixth  layer  of  muscles  comprises  the  following : 

1.  The  complexus,  or  semispinalis  capitis. 

2.  The  semispinalis  dorsi  in  the  dorsal  region. 

3.  The  semispinalis  colli  in  the  cervical  region. 

4.  The  multifidus  spinae,  found  in  all  regions  of  the  spine. 

5.  The  rotatores  spinae,  found  in  the  thoracic  region. 
Describe  the  complexus  muscle. 

This  muscle  (Figs.  283  and  284)  is  covered  by  the  splenius,  with  its  two 
divisions,  and  the  trapezius.  In  turn,  this  complexus  covers  the  muscles  that 
make  the  boundaries  of  the  suboccipital  triangle,  thereby  forming  the  roof  of  this 
important  surgical  area — the  suboccipital  triangle.  The  occipital  artery  lies  on 
the  muscle  ;  the  suboccipital  and  great  occipital  nerves  are  under  the  muscle, 
being  parts  of  the  contents  of  the  suboccipital  triangle.  The  origin  of  the  muscle 
is  from  :  (i)  The  articular  processes  of  the  cervical  vertebra?  from  the  third  to  the 
sixth  ;  the  transverse  processes  of  the  seventh  cervical  and  the  six  upper  thoracic 
vertebras.  The  insertion  is  into  the  occipital  bone,  between  the  middle  and 
inferior  curved  or  nuchal  lines.  (Fig.  278.)  Nerve-supply:  (i)  The  suboccipital 
or  posterior  primary  division  of  the  first  cervical  ;  (2)  the  great  occipital  or 
posterior  primary  division  of  the  second  cervical  ;  (3)  the  posterior  primary 
divisions  of  the  third,  fourth,  and  fifth  cervical  nerves. 


406 


PRACTICAL    ANATOMY. 


Obliquua  superior 


Rectus  capitis  posticus  major  - 
Obliquus  inferior 
Trachelo-mastoid 


Transversalis  oolli 
Cervicalis  ascendena  


Accessorius  ad  ilio- 
costalem 


Ilio-costalis 


Insertion  of  ilio-costalia 
upon  lumbar  transverse 
processes 


Rectus  capitis  posticus  minor 


—  SEVENTH  CERVICAL  VERTEBRA 


LongisBirnus  dorai 


TWELFTH  THORACIC  VERTEBRA 


FIFTH  LUMBAR  VERTEBRA 
Erector  spinae 


IMG.  284.— TIIK  FII-TII   LAYKK  OF    IMF  MUSCLKS  Of   mi-    BACK,  AI-TER  SITAKATINC;    HIK 

i  H    I  I  l:     AM)    MlMUI.K    DlV|sM>NS. 


THE   BACK.  407 

Describe  tlic  semispinalis  dorsi. 

The  idea  in  the  name  is  founded  on  the  facts  :  (i)  That  one  of  the  muscle  is 
inserted  into  the  spines,  and  (2)  that  the  muscle  is  situated  in  the  thoracic  or  dorsal 
region  of  the  spine.  (Fig.  285.)  The  muscles  composing  the  series  are  small  and 
tendinous.  They  extend  obliquely  inward  and  upward,  from  their  origin,  on  the 
back  of  the  transverse  processes  of  the  thoracic  vertebrae,  from  the  sixth  to  the 
tenth,  to  their  insertion  into  the  spines  of  the  last  two  cervical  and  the  first, 
second,  third,  and  fourth  thoracic.  The  nerve-supply  is  from  the  posterior 
primary  divisions  of  the  thoracic  nerves.  Remove  this  muscle  and  you  expose 
the  multifidus  spinae  below.  The  muscle  is  covered  by  the  spinalis  dorsi 
and  latissimus  dorsi — the  inner  and  middle  parts  of  the  erector  spins,  you  will 
remember. 

Describe  tJie  semispinalis  colli. 

The  verbal  idea  is  the  same  in  this  as  in  the  preceding  muscle.  The  muscle 
is  located  in  the  cervical  region  ;  it  is  inserted  into  the  spines  of  the  cervical 
vertebrae,  from  the  second  to  the  fifth  inclusive.  (Fig.  285.)  The  muscle  originates 
from  the  transverse  processes  of  the  five  or  six  upper  thoracic  vertebrae.  The 
muscle  is  covered  by  the  complexus  ;  under  it  is  the  multifidus  spinae.  Between 
the  complexus  and  semispinalis  colli  you  will  find  :  (i)  Branches  of  the  posterior 
cervical  nerves  ;  (2)  an  anastomosis  between  the  arteria  princeps  cervicis,  a  branch 
of  the  occipital,  and  the  arteria  profunda  cervicis,  a  branch  of  the  superior  inter- 
costal. In  ligatfon  of  the  common  carotid  and  subclavian  arteries  blood  may 
reach  both  the  hand  and  brain  by  this  channel. 

Describe  the  nmltifidus  spines. 

The  multifidus  spinae  is  found  in  every  region  of  the  spine.  In  the  sacral  and 
lumbar  regions  it  is  thick  and  fleshy  ;  in  the  thoracic  and  cervical  regions  it  is 
thin  and  aponeurotic.  This  muscle  has  the  following  origins,  which  must  be 
carefully  learned  before  this  muscle  can  be  dissected  understandingly  : 

(i)  From  the  deep  surface  of  the  erector  spinae.  This  fact  of  origin  makes  the 
dissection  of  the  muscle  a  difficult  task,  except  in  cases  of  zinc  or  formaline  pre- 
pared bodies  where  the  cadavers  have  had  a  year  to  become  very  hard  ;  (2) 
from  the  groove  between  the  sacral  spines  and  rudimentary  articular  processes 
of  the  sacrum  ;  (3)  from  the  mammillary  processes  of  the  lumbar  vertebrae  ;  (4) 
the  transverse  processes  of  all  the  thoracic  vertebrae  ;  (5)  the  articular  processes 
of  the  cervical  vertebrae  from  the  fourth  to  the  sixth,  and  from  the  transverse 
process  of  the  seventh  cervical.  The  segments  making  up  the  collective  multi- 
fidus spinae  from  these  diverse  regions  are  inserted  as  follows  :  into  the  lower 
borders  of  the  vertebral  spines,  from  the  fifth  lumbar  to  the  second  cervical. 
The  nerve-supply  of  the  multifidus  spinae  is  from  the  posterior  primary  divisions 
of  the  spinal  nerves,  from  the  second  cervical  to  the  third  sacral  nerve.  This 
muscle  covers  the  rotatores  spinae. 

Describe  the  rotatores  spiiue. 

These  are  in  the  region  of  the  thorax.  They  derive  their  name  from  the 
rotatory  action  they  exert.  Of  these  muscles  there  are  eleven  pairs.  They 
originate  from  the  back  and  upper  part  of  the  transverse  processes,  and  are 
inserted  into  the  lower  border  of  the  lamina  of  the  next  vertebra  above.  They 
are  in  relation  above  with  the  multifidus  spinae.  Nerve-supply,  the  posterior 
primary  divisions  of  the  spinals. 

Name  and  describe  the  seventh  layer  of  muscles  of  the  back. 

(i)  The  interspinales  arise  from  the  upper  surface  of  the  spine  of  a  lower,  and 
are  inserted  into  the  lower  surface  of  the  spine  of  the  vertebra  immediately 
above.  These  muscles  are  very  small.  Nerve-supply,  the  posterior  primary 
divisions  of  the  spinals.  (2)  The  intertransversales  arise  from  the  transverse 
process  below  and  are  inserted  into  the  one  above.  They  are  small  muscles. 


408 


PRACTICAL   ANATOMY. 


They  are  principally  in  the  cervical  and  lumbar  regions.    Nerve-supply,  from  the 
spinals  as  they  emerge  from  the  intervertebral  foramina. 


Compleius 

Obliquua  superior 

Reotua  capitia  poaticua  major 

Obliquua  inferior 

Multifldua  spinae 

Semispinalia  oolli 
Cervioalia  aacendens 

LonKiaaimus  dorsi 


Levator  eoatse 


Longiesimus  dorai 
Ilio-ooataliB 

Obliquus  internua 
Lumbar  fascia 

Ilio-coatalia 


Kectua  capitis  poaticub 
minor 


SEVENTH  CERVICAL  VERTEBRA 


Semispmalis  dorai 


—  Multifldua  apinae 


TWELFTH  THORACIC  VERTEBRA 


Multifldua  apinae 


FIFTH  LUMBAR  VERTEBRA 


Itifldus  spiuce 


l-ii..  285.  —  TIIK  SIMM    I.AM'.K  en-   TIII-:  Mi  M  i.i-s  01    im-.   I;\CK. 


I.     The    Complcxns.  —  Remove    the  longissimus    dorsi    and    its    continuation 
through   the    neck    and    to  the  head  —  the   transvcrsalis   colli   and   the   trachdo- 


THE   BACK.  409 

mastoid.  The  complexus  will  be  seen  arising  from  :  (i)  The  back  of  the  artic- 
ular processes  of  the  cervical  vertebrae  from  the  third  to  the  sixth  ;  (2)  the  back 
of  the  transverse  processes  of  the  seventh  cervical  and  the  six  upper  thoracic 
vertebrae  ;  (3)  generally  also  by  an  inner  head  from  the  spine  of  the  seventh  cer- 
vical vertebra.  It  is  inserted  into  the  occipital  bone,  between  the  superior  and 
inferior  nuchal  lines.  (Fig.  283.) 

Carefully  detach  the  insertion  of  this  muscle  and  you  will  expose  :  (i)  The 
suboccipital  triangle,  containing  the  vertebral  artery  and  the  suboccipital  nerve  ; 
(2)  on  the  under  part  of  the  muscle  you  will  find  the  suboccipital  nerve  and  the 
great  occipital  nerve  ;  (3)  the  recti  and  oblique  muscles  ;  (4)  the  semispinalis  colli, 
coming  to  a  large  abrupt  insertion  into  the  spine  of  the  axis. 

The  suboccipital  triangle  has  (Fig.  285) : 

A  roof  formed  by  the  complexus  muscle. 

A  floor  formed  by  the  arch  of  the  atlas  and  atlo-occipital  ligament. 

An  inner  border  formed  by  rectus  capitis  posticus  major. 

A  lower  border  formed  by  inferior  oblique  muscle. 

An  upper  border  formed  by  superior  oblique  muscle. 

The  contents  are  the  vertebral  artery  and  suboccipital  nerve. 

It  is  traversed  by  the  great  occipital  nerve. 

The  suboccipital  muscles  (Fig.  285) : 

1.  The  obliquns  capitis  inferior,  which  extends  from  the  spine  of  the  axis  to 
the  transverse  process  of  the  atlas. 

2.  The  obliquns  capitis  superior,  which  extends  from  the  transverse  process  of 
the  atlas  to  the  inferior  nuchal  line  of  the  occipital  bone. 

3.  The  rectus  capitis  posticus  major,  which    extends  from  the  spine  of  the 
axis  to  inferior  nuchal  line,  middle  one-third. 

4.  The  rectus  capitis  posticus  minor  extends  from  the  tubercle  of  the  atlas  to 
the  inner  one-third  of  the  inferior  nuchal  line. 

5.  The  rectus  capitis  later  alls  extends  from  the  lateral  mass  of  the  atlas  to  the 
jugular  process  of  the  occipital  bone. 

Now  remove  from  its  origin  (i)  the  complexus,  and  as  you  turn  the  body  of 
the  muscle  from  the  semispinalis  colli,  you  will  see  between  these  two  muscles 
some  vessels — the  anastomosis  between  the  arteria  profunda  cervicalis,  a  branch 
of  the  first  or  superior  intercostal,  and  the  arteria  princeps  cervicis,  a  branch  of 
the  occipital.  (Fig.  40.)  You  will  find  a  large  mass  of  veins  here,  too.  In 
cases  of  ligation  of  the  subclavian  or  common  carotid  artery,  this  is  the  principal 
channel  by  which  the  blood  passes  to  form  a  collateral  circulation.  (2)  Remove 
any  remaining  part  of  the  spinalis  dorsi  or  longissimus  dorsi  and  make  your 
work  look  like  figure  285. 

You  have  remaining  the  other  members  of  the  sixth  and  seventh  groups  : 
(i)  The  semispinalis  dorsi ;  (2)  the  semispinalis  colli;  (3)  the  multifidus  spinae. 
These  were  explained  under  the  head  of  "  Analysis  of  the  Simple  Movements  of 
the  Spinal  Column,"  to  which  you  are  referred  on  page  395.  Remove  the  three 
muscles  just  given,  and  dissect  (4)  the  rotatores,  (5)  the  intertransversales,  (6)  the 
interspinales,  according  to  their  previous  description,  just  referred  to. 

i .   Give  the  cutaneous  nerve-supply  of  the  back. 

The  scalp  is  supplied  by  (i)  the  great  occipital ;  (2)  the  suboccipital ;  (3)  the 
third  occipital.  These  are  all  spinal  nerves.  The  remainder  is  supplied  by  the 
posterior  divisions  of  the  spinal  nerves.  Next  the  spine  you  will  see  some  small 
nerves  coming  through  to  the  skin.  (Fig.  279.)  These  are  cutaneous  twigs 
from  the  internal  branches  of  the  posterior  divisions  of  the  spinal  nerves.  A 
little  distance  from  the  spine  you  will  see  nerves  coming  through  the  trapezius 
and  latissimus  dorsi.  These  are  the  external  cutaneous  branches  of  the  posterior 
divisions  of  the  spinal  nerves. 
27 


410  PRACTICAL  ANATOMY. 

2.  Explain  internal  and  external  brandies  of  t/ie  posterior  divisions  of  tJie  spinal 
nerves. 

The  internal  branches  are  small,  and  supply  the  sixth  and  seventh  groups  of 
muscles  and  the  skin  on  each  side  of  the  spine  for  an  inch  or  two  inches.  The 
external  branches  supply  all  the  other  proper  muscles  of  the  back  and  the 
remainder  of  the  skin.  All  the  thirty-one  pairs  of  posterior  divisions  of  spinal 
nerves  divide  as  previously  indicated,  except  the  first.  This  is  called  the  suboccipital 
nerve. 

3.  Define  ivhat  is  meant  by  proper  muscles  of  the  back. 

All  those  muscles  not  acting  on  the  shoulder  girdle  ;  those  under  the  verte- 
bral aponeurosis. 

4.  Give  a  description  of  the  superficial  fascia  of  the  back. 

It  is  very  thick  and  dense,  and  contains  granular  fat.  Abscesses  often  form 
here.  A  favorite  place  for  carbuncles  is  in  the  superficial  fascia  of  the  neck. 

5.  Name  the  muscles  of  the  back  not  supplied  principally  by  the  posterior  divi- 
sions of  the  spinal  nerves. 

The  trapezius,  the  latissimus  dorsi,  the  levator  anguli  scapulae,  and  the  rhom- 
boids, major  and  minor. 

SHORT  SUMMARY  OF  THE  CRANIAL  NERVES. 

Hoiv  arc  the  cranial  nerves  classified  ? 

According  to  the  new  classification  of  cranial  nerves  there  are  twelve  pairs, 
enumerated  serially  from  before  backward,  from  the  olfactory,  or  first,  to  the 
hypoglossal,  or  twelfth,  inclusive.  This  classification  was  proposed  by  Soemmer- 
ing  in  1778.  Prior  to  this  time  the  classification  of  Willis  had  been  in  use  for 
more  than  a  century,  by  which  classification  only  ten  pairs  were  recognized. 

Make  a  further  distinction  between  the  classifications  of  the  cranial  nerves  by 
Socmmcring  and  Willis. 

In  the  seventh  pair  Willis  included  both  the/ada/,  a  nerve  of  motion,  and 
the  auditory,  a  nerve  of  the  special  sense  of  hearing.  The  eighth  pair  of  Willis 
included  the  ninth,  tenth,  and  eleventh  nerves  of  our  classification.  The  ninth 
pair  of  Willis  included  the  hypoglossal,  and  the  tenth  pair  of  Willis  included  the 
first  cervical,  called  the  suboccipital  nerve. 

What  is  understood  by  superficial  and  deep  origins  of  cranial  nerves  f 

By  the  former  is  meant  the  place  where  the  nerve  is  seen  attached  to  the 
surface  of  the  brain  (Fig.  92)  ;  by  the  latter  is- meant  the  place  deeply  located, 
called  a  nucleus  of  gray  matter,  to  which  the  motor  part  of  nerves  can  be  traced. 

Docs  not  tlie  sensorv  part  of  nerves  also  have  a  deep  origin  f 

Properly  speaking,  the  sensory  parts  of  nerves  have  their  origin  in  the  cells 
of  the  posterior  root  ganglia  of  the  nerve-trunks,  to  which  ganglia  special  atten- 
tion must  be  given  in  the  dissection  of  both  cranial  and  spinal  nerves.  The 
sensory  fibres  originating  in  the  ganglia  grow  inward  to  this  nuclei,  and,  as  far 
as  is  known,  form  there  no  direct  connection  with  the  nerve-cells. 

Is  there  any  correspondence  between  the  origins  of  the  cranial  nerves  and  the 
origins  of  the  spinal  nerves  f 

Yes  ;  each  has  a  superficial  and  a  deep  origin.  The  superficial  origin  of  the  spinal 
nerves  is  readily  seen  on  removing  the  spinal  cord  from  its  neural  canal.  The 
deep  origin  of  the  spinal  nerves  is  from  tin-  anterior  and  posterior  horns  of  the 
gray  crescents  of  the  interior  horns  of  the  spinal  cord. 

\VItat  further  resemblance  between  crania/  and  spinal  nerves  may  be  mentioned / 

(l)  Fibres  from  the  deep  origin  of  eaeh  pass  upward  and  are  connected  with 
the  cortex  of  the  cerebrum  ;  (2)  the  pneumo^astric  nerve  arises  by  motor  and 
sensory  roots  from  nuclei  which  are  derivatives  of  the  anterior  and  posterior 


THE   BACK.  411 

horns  respectively  of  the  spinal  cord  ;  (3)  the  ganglion  on  the  sensory  root  of 
the  fifth  cranial  nerve  and  the  ganglion  on  the  root  of  the  vagus  are  homologous 
to  the  ganglia  on  the  posterior  roots  of  the  spinal  nerves  ;  (4)  cases  are  recorded 
of  absence  of  the  ganglion  on  the  posterior  root  of  the  first  spinal  or  suboccipital 
nerve  ;  (5)  cases  are  recorded  of  the  hypoglossal — the  twelfth  cranial — nerve 
having  a  posterior  root  with  a  ganglion.  Possibly  anomalous  cases  like  those 
cited  in  4  and  5  may  account  for  and  even  justify  the  tenth  cranial  nerve — the 
hypoglossal — in  the  classification  by  Willis. 

In  iv  hat  respects  do  spinal  nerves  differ  from  cranial  nerves  / 

In  the  following  respects  :  (i)  Spinals  arise  from  the  spinal  cord  ;  (2)  spinals 
have  an  anterior  motor  and  a  posterior  sensory  root  ;  (3)  spinals  have  a  ganglion 
on  each  posterior  root ;  (4)  spinals  have  no  special  sense  nerves. 

State  where  the  ganglia  of  the  posterior  or  sensory  roots  of  the  spinal  nerves  may 
be  found  in  dissecting. 

The  rule  is  that  these  ganglia  occupy  the  posterior  root  of  the  spinal  nerve, 
just  behind  the  union  of  the  anterior  and  posterior  roots,  in  the  intervertebral 
foramen. 

Are  there  any  exceptions  to  the  rule  governing  the  location  of  the  spinal 
ganglion  / 

Yes  ;  the  ganglia  of  the  first  and  second  cervical  nerves  lie  on  the  neural 
arches  of  the  atlas  and  axis.  The  ganglia  of  the  sacral  and  coccygeal  nerves 
are  in  the  spinal  canal. 

Describe  the  vagus  or  pneumogastric  nerve. 

This  nerve  is  the  tenth  cranial,  according  to  the  classification  of  Soemmering  ; 
it  is  also  called  the  nervus  vagus  and  the  nervus  par  vagam.  The  nerve  leaves 
the  base  of  the  cranium  by  the  central  part  of  the  jugular  foramen  with  the  spinal 
accessory  and  glosso-pharyngeal  nerves. 

Where  is  the  ganglion  of  the  root  of  the  vagus  located,  and  to  what  does  it  corre- 
spond morphologically  ? 

It  is  located  in  the  jugular  foramen,  and  corresponds  to  the  spinal  ganglion  on 
the  posterior  roots  of  the  spinal  nerves. 

What  is  the  importance  of  the  ganglion  of  the  root  of  the  vagus  nerve  ? 

It  has  connections  with  the  sympathetic,  spinal  accessory,  glosso-pharyngeal, 
and  facial  nerves.  (Fig.  293.) 

Where  is  the  ganglion  of  the  trunk  of  the  vagus  nerve  and  ivliat  its  impor- 
tance ? 

It  is  a  little  below  the  ganglion  of  the  root  and  below  the  base  of  the  skull. 
Its  importance  is  due  to  the  fact  that  branches  are  given  off  from  it  to  the  sympa- 
thetic, to  the  cervical  nerves,  and  to  the  hypoglossal  nerve  ;  also  the  accessory 
part  of  the  spinal  accessory  nerve  joins  the  vagus  at  this  point.  (Fig.  293.) 

Describe  the  olfactory  nerve. 

The  olfactory  nerve,  as  generally  understood,  is  in  reality  a  dismembered  part 
of  the  fore-brain  of  the  foetus.  It  consists  of  four  parts,  as  may  be  appreciated  by 
consulting  figure  286. 

1.  The  olfactory  roots,  three  in  number. 

2.  The  olfactory  tract,  a  slender  bundle. 

3.  The  olfactory  bulb,  resting  on  the  cribrosa. 

4.  The  olfactory  filaments,  about  twenty  in  number. 
Name  and  give  the  source  of  the  olfactory  roots. 

The  middle  root  is  attached  to  the  under  surface  of  the  frontal  lobe  ;  the 
internal  root  to  the  gyrus  fornicatus  ;  the  external  root  to  the  temporo-sphenoidal 
lobe.  The  roots  meet  to  form  the  olfactory  tract.  The  tract  becomes  bulbous 
and  occupies  a  fissure  on  the  under  surface  of  the  frontal  lobe  of  the  cerebrum, 
called  the  olfactory  sulcus.  The  olfactory  nerves  are  given  off  from  the  under 


412 


PRACTICAL   ANATOMY. 


part  of  the  bulb.  The  nerves  are  about  twenty  in  number  on  each  side.  They 
pass  through  the  olfactory  foramina  in  the  cribriform  plate  of  the  ethmoid  bone. 
In  their  course  through  the  foramina,  the  nerves  are  invested  by  a  sheath  of 
dura  mater.  (Fig.  87.)  The  olfactory  nerve  filaments  are  distributed  to  the 
mucous  membrane  of  the  upper  and  middle  turbinated  bones,  and  to  a  corre- 
sponding part  of  the  septum  nasi.  (Fig.  75.) 

Describe  tJie  optic  nerve. 

This  nerve  is  the  special  nerve  of  sight,  being  distributed  solely  to  the  eye- 
ball. The  commissure  is  the  place  on  the  sphenoid  bone  where  the  two  sides 


ffulA 


Ot feretory  filaments 

FIG.  286. — FIRST  CRANIAL  NERVE,  OLFACTORY. 

are  connected.  The  optic  nerve  proper  is  between  the  commissure  and  the  eye- 
ball ;  the  optic  tract  is  between  the  commissure  and  the  brain. 

Describe  the  optic  tract. 

It  arises  (Fig.  92)  :  (i)  From  the  pulvinar  of  the  optic  thalamus  ;  (2)  from 
the  geniculate  body  ;  (3)  from  the  upper  quadrigeminal  body.  The  tract  crosses 
the  crus  cerebri  (Fig.  92),  being  closely  attached  thereto,  and  terminates  in  the 
optic  chiasma  or  commissure.  The  student  will  recall  the  fact  that  the  optic 
chiasma  and  the  optic  tracts  assist  the  crura  cerebri  and  pons  Varolii  in  forming 
the  boundaries  of  the  interpeduncular  space.  (Fig.  92.) 


Longitudinal  Fibers- 
Decussating  Fibers 
Intcrcerehral  Fibers 
Inter-retinal  Fibers 


FIG.  287. — SECOND  CRANIAL  NIRVK,  Orru. 


Describe  the  optic  ncri'c  proper. 

This  nerve  extends  from  the  chiasma  to  the  eyeball.  It  leaves  the  cranium 
by  the  optic  foramen,  in  the  sphenoid  bone,  in  company  with  the  ophthalmic 
artery.  The  nerve  has  a  cranial  part  and  an  orbital  part ;  the  latter  is  flexuous, 
to  accommodate  the  movements  of  the  eyeball,  and  is  surrounded  by  ciliary 
vessels  and  nerves. 

///  practical  anatomy  i^Iicrc  do  you  find  tJic  artcria  ccntralis  retuuc  / 

This  must  In-  seen  in  a  dissection  of  the  contents  of  the  orbit.  (Fig.  103.) 
You  will  find  this  artery  piercing  the  under  part  ojf  the  nerve,  and  about  midway 
between  the  optic  forair.en  and  the  globe. 


THE   BACK.  413 

The  she  at J i  of  the  optic  nerve  is  derived  from  what  source  / 

It  is  derived  from  the  dura  mater  coming  through  the  optic  foramen  and  de- 
laminating  ;  one  layer  ensheathes  the  optic  nerve,  the  other  forms  the  orbital 
periosteum.  (Fig.  95.) 

The  third  cranial  nerve — the  motor  oculi — supplies  :  (i)  The  ciliary  muscle  of 
the  eyeball  ;  (2)  the  sphincter  muscle  of  the  iris  ;  (3)  all  the  muscles  of  the  eye- 
ball except  the  superior  oblique  and  the  external  rectus. 

This  nerve  arises  beneath  the  floor  of  the  aqueduct  of  Sylvius.  On  removing 
the  brain  from  the  cranium,  you  see  the  nerve  between  the  crura  cerebri.  (Fig. 
92.)  The  nerve  pierces  the  dura  midway  between  the  anterior  and  posterior 


FIG.  288. — THIRD  CRANIAL  NERVE,  MOTOR  OCULI. 

clinoid  processes,  and  enters  the  cavernous  sinus  ;  in  the  sinus  it  lies  above  and 
internal  to  the  fourth  nerve.  (Figs.  86—88.)  The  nerve  divides  behind  the 
sphenoidal  fissure  into  a  superior  and  an  inferior  division.  (Fig.  86.)  These  two 
divisions  enter  the  orbit  by  the  sphenoidal  fissure,  passing  between  the  two  heads 
of  the  external  rectus  muscle.  (Fig.  101.)  The  superior  division  supplies  the 
superior  rectus  muscle  and  the  levator  palpebrae  ;  the  inferior  division  has  the 
remaining  part  of  the  distribution  of  the  third  nerve. 

\VJiat  can  yon  say  of  the  fourth  cranial,  or  patJieticns? 

It  is  also  called  the  trochlear  nerve,  from  the  fact  that  it  supplies  the  superior 
oblique  muscle  of  the  eyeball  only.  This  nerve  has  a  long  course  in  the  cranial 
cavity.  In  dissection  you  see  the  nerve  just  under  the  margin  of  the  anterior 


FIG.  289. — FOURTH  CRANIAL  NERVE,  TROCHLEAR. 

free  border  of  the  tentorium  cerebelli,  and  soon  piercing  the  dura  to  the  outer 
side  of  the  posterior  clinoid  process,  to  gain  the  cavernous  sinus.  (Fig.  98.) 
This  nerve  is  the  smallest  of  the  cranial  nerves  ;  it  enters  the  orbit  by  the  sphe- 
noidal fissure.  The  nerve  has  its  'deep  origin  in  the  floor  of  the  aqueduct  of 
Sylvius. 

Describe  briefly  the  fifth  cranial  or  trifacial  nerve. 

This  nerve  is  specialized  almost  exclusively  for  the  prehension  and  mastication 
of  food  directly  or  indirectly.  It  will  be  noted  that  the  relation  between  this  and 
other  nerves  depends  upon  the  near  or  remote  association  these  latter  bear  to  the 
functions  of  the  fifth  nerve.  Take  notice,  then,  of  the  function  of  the  trigeminus, 


414 


PRACTICAL  ANATOMY. 


as  follows  :  (i)  The  fifth  nerve  supplies  with  sensation  all  the  teeth.  (2)  The  fifth 
nerve  supplies  with  sensation  the  gums,  by  little  nerves  called  the  nervi  gingivales. 
(3)  The  fifth  nerve  supplies  the  sides  of  the  tongue,  and  the  anterior  one-half  of 
the  same  through  its  lingual  or  gustatory  branch.  (4)  The  fifth  nerve  supplies 
the  muscles  of  mastication  with  motion — muscles  whose  function  is  to  move  the 
mandible.  (5)  The  fifth  nerve  supplies  the  temporo-mandibular  articulation,  be- 
cause the  muscles  it  supplies  move  this  articulation.  The  same  branch  that  sup- 
plies the  articulation,  the  auriculo-temporal,  also  supplies  the  drum  of  the  ear 
and  the  auditory  canal,  because  these  parts  are  secondary  in  the  acquisition  of 
food.  (6)  The  fifth  nerve  supplies  the  skin  covering  the  fullest  region  of  the 


FIG.  290. — FIFTH  CRANIAL  NI.KVK. 


muscles  of  mastication  ;  in  round  numbers,  the  cutaneous  region  in  front  of  a  line 
passing  from  side  to  side  through  the  auditory  meatuses  is  supplied  by  the  auri- 
culo-temporal, supraorbital,  infraorbital,  and  mental  branches  of  this  nerve.  (7) 
The  fifth  nerve  supplies  the  anterior  belly  of  the  digastric  muscle  and  the  mylo- 
hyoid  muscle,  but  these  muscles  are  depressors  of  the  mandible.  (8)  The  fifth 
nerve  has  numerous  connections  with  the  facial  nerve.  Study  the  facial  anil 
temporal  relations  between  these-  two  nerves  ;  tin-  chorda  tympani  ;  the  otic,  sub- 
maxillary,  and  Meckel's  ganglia.  The  trifacial  nerve  supplies  the  muscles  of 
mastication  with  motion,  and  the  skin  covering  these  muscles. 

ll'/itif  can  you  .sv/r  of  tlic  si.vtli  cranial  )icrvc  / 

This  nerve  is  distributed  solely  to  the  external  rectus  muscle.      It  arises  from 


THE   BACK. 


415 


the  floor  of  the  fourth  ventricle.  It  may  be  seen  in  dissection  piercing  the  dura 
below  and  internal  to  the  fifth  nerve.  (Fig.  88.)  In  the  cavernous  sinus  the 
nerve  lies  on  the  outer  side  of  and  is  attached  to  the  internal  carotid  artery. 
(Fig.  88.)  In  the  sinus  the  sixth  nerve  is  joined  by  sympathetic  filaments  from 
the  cavernous  plexus,  and  receives  a  twig  from  the  ophthalmic  branch  of  the 
fifth  nerve.  (Fig.  98.) 

The  Seventh  or  Facial  Nerve.  —  (i)  Leaves  the  cranium  by  the  internal  audi- 
tory meatus  in  company  with  the  auditory  or  eighth  cranial  nerve  and  the  audi- 
tory artery,  a  branch  of  the  basilar  artery.  (2)  In  the  internal  auditory  canal  it 
is  connected  to  the  auditory  nerve  by  the  pars  intermedia,  and  enters  a  separate 
bony  canal,  called  the  aqueductus  Fallopii,  one-quarter  of  an  inch  from  the  in- 
ternal auditory  meatus.  (3)  On  nearing  the  tympanum  the  nerve  turns  sharply 
backward  and  presents  an  enlargement,  called  the  intumescentia  gangliformis  (gen- 


Supnavrbifal  3?!1 


FIG.  291.  —  SEVENTH  CRANIAL  NERVE,  FACIAL,  OR  PORTIA  DURA. 

Great  petrosal,  to  form  Vidian  with  No.  5.  2.  Small  petrosal,  to  otic  ganglion.  3.  External  petrosal, 
to  plexus  on  mid-meningeal  artery.  4.  Tympanic  branch  to  stapedius,  etc.  5.  Branch  from  carotid 
plexus  making  Vidian,  with  No.  I.  6,  7.  Branches  to  auriculo-temporal  of  fifth.  8.  Branch  to 
auricular  of  vagus.  M.  The  ganglion  of  Meckel.  O.  A.  F.  Orifice  of  aqueductus  fallopii. 


iculate  ganglion).  (4)  From  the  geniculate  ganglion  are  the  following  branches  : 
(a]  The  large  superficial  petrosal  to  Meckel's  ganglion.  This  branch  leaves  the 
cranium  by  the  foramen  lacerum  medium,  and  joins  a  branch  from  the  carotid 
sympathetic  plexus,  called  the  large  deep  petrosal,  to  form  the  Vidian  nerve.  (/?) 
The  small  superficial  petrosal  to  the  otic  ganglion.  This  nerve  leaves  the 
cranium  by  the  canalis  innominatus,  a  small  opening  between  the  foramen  ovale 
and  the  foramen  spinosum,  in  the  greater  wing  of  the  sphenoid  bone.  This  branch 
receives  a  communicating  twig  from  the  tympanic  branch  of  the  glosso-pharyn- 
geal  nerve,  (r)  The  external  superficial  petrosal  nerve,  to  join  the  sympathetic 
on  the  middle  meningeal  artery.  (5)  The  facial  nerve  traverses  the  middle  ear 
in  its  bony  canal,  traversing  between  the  roof  and  inner  wall,  and  between  the 
inner  wall  and  the  posterior,  successively,  emerging  at  the  stylo-mastoid  foramen. 
(6)  In  the  middle  ear  the  nerve  gives  off  (a]  a  small  branch  to  the  stapedius 
muscle  ;  (b]  the  chorda  tympani,  which  supplies  the  submaxillary  and  sublingual 


416 


PRACTICAL  ANATOMY. 


glands  with  secretory  and  vaso-dilator  fibres,  and  the  anterior  part  of  the  tongue 
with  taste  fibres.  The  facial  supplies  the  stylo-hyoid,  the  posterior  bell}-  of  the 
digastric,  all  the  dermal  muscles  about  the  ear,  the  posterior  belly  of  the  occipito- 
frontalis,  and  all  the  muscles  of  facial  expression.  (7)  The  facial  nerve  commu- 
nicates with  the  three  divisions  of  the  fifth  on  the  face  ;  with  the  spheno-palatine. 
otic,  and  submaxillary  ganglia  ;  with  the  auditor}',  vagus,  sympathetic,  and  glosso- 
pharyngeal  nerves. 

Dcsoibc  briefly  the  auditory  nerve. 

This  is  the  eighth  cranial  nerve.  It  leaves  the  cranium  by  the  internal  auditory 
meatus  with  the  auditory  artery — a  branch  of  the  basilar — and  the  seventh  or  facial 

OPHTHALMIC     SUPERIOR  MA.\I I.L.I  I!  Y      1. \7-7-.7.' ini;  MAXILLA  I!  Y 
\ 


GASSEJ;I.\\ 


x.i/.iA.A. 

FICIAL  I'ETHOSAI. 


/••/r  7.1  A, 


r. i. v.i  A /.s  . 

TUBARIVS 


FENESTRA  OVA  US  AM> 
ROTUNDA  I\  Till':  /.V.V /•;/.' 
MM  I.L 


FACIAL  NERVE 


EXTERNAL 
SUPERFICIAL 
PETROSAL 


ANTERIOR  WALL 


POSTERIOR  WALL 


FIG.  292. — Box  ILLUSTRATION  OF   SEVENTH  CRANIAL  NERVK  IN  RELATION  TO  THE  MIDDLE 

EAR  OR  TYMPANUM. 

For  puqx>ses  of  aiding  ihe  memory,  the  tympanum  is  compared  to  a  box.     The  reader  is  referred  to 
page  135  for  a  full  description  of  the  figure. 


nerve.  In  the  auditory  canal  it  communicates  with  the  seventh  nerve  by  the  pars 
intermedia.  The  eighth  is  the  nerve  of  the  special  sense  of  hearing.  (For  the 
distribution  of  this  nerve  see  Morris.) 

Describe  the  glosso-pliaryngeal  nerre. 

This  is  the  ninth  cranial  nerve.  It  escapes  from  the  cranium  by  the  jugular 
foranu-n  with  the  tenth  and  eleventh  nerves  and  the  jugular  vein.  The  nerve 
has  two  ganglia:  (i)  The  jugular  and  (2)  the  petrosal  ganglion.  The  ninth 
nerve  distributes  branches  to  the  mucous  membrane  of  the  tongue,  pharynx, 
tympanum,  and  also  to  the stylo-phary ngeus  muscle.  It  supplies  the  otic  gano- 
lion  ria  its  communications  with  the  small  superficial  petrosal  branch  of  the 


THE   BACK.  417 

seventh  nerve.  This  nerve  communicates  with  the  third  division  of  the  fifth 
nerve  ;  with  the  facial,  sympathetic,  and  vagus. 

What  can  you  say  of  the  function  of  the  vagus  ? 

In  animals  less  highly  specialized  than  man  the  term  pneumogastric 
expresses  practically  all  that  can  be  said  of  this  nerve,  since  in  its  wandering 
distribution  it  supplies  the  organs  of  voice  and  respiration  with  motion  and  sensa- 
tion ;  the  organs  of  circulation  and  digestion  with  motion  only.  The  vagus, 
then,  has  to  do  with  the  two  greatest  sources  of  metabolism  :  the  ingestion  of  food 
and  air.  Man  is  not  all  stomach  and  lung.  By  synecdoche,  however,  stomach 
may  represent  a  complicated  digestive  apparatus,  and  lung  an  equally  differ- 
entiated apparatus,  in  which  the  blood  throws  off  CO2  and  loads  up  with  O, 
according  to  the  law  of  the  diffusion  of  gases.  Now,  the  student  must  remember 
this  :  The  names  of  the  branches  of  the  vagus  nerve  will  be  governed  and  deter- 
mined by  the  following  conditions  : 

1.  The  arbitrary  subdivision  of  the   alimentary  canal,  to  which   the  vagus  is 
distributed. 

2.  The  arbitrary  subdivisions  of  the  respiratory  system,  to  which  the  vagus  is 
distributed. 

3.  The    sympathetic    nerve-branches   to   both   the    respiratory  and  digestive 
systems,  since  the  sympathetic  is  the  nerve  of  organic  life. 

4.  The  organs,  or  systems  of  organs,  associated  secondarily  with  the  respira- 
tory and  digestive  processes.     The  tongue,  for  example,  is  associated  with  both 
respiratory  and  digestive  processes,  and  while  this  organ  has  its  own  specific  nerve- 
supply,  upon  which  its  sensation  and  motion  depend,  still,  the  orderly  adjustment 
of  internal  to  external   relations  could   not  occur,  were  there  no  communication 
between  the  nerve-supply  of  the  tongue,  which  forces  food  into  the  pharynx,  and 
the  organs  that  deliver  this  food  to  the  stomach.      In  like  manner  there  must  be 
unanimity  of  action  between  the  lungs,  vocal  cords,  and  tongue,  for  vocalizing  and 
linguistic  purposes  ;  this   unanimity  must  depend  on  an  uninterrupted  communi- 
cation  between   the  nerve-supply  of  the  tongue  and  the  vagus  nerve.     Observe 
the  difference  in  facial  expression  of  the  two   men,  the   one  of  whom  is  in  the 
nausea  period  of  a  malarial  attack,  the  other  of  whom  is  enjoying  an  after-dinner 
cigar.      The  facial  nerve  supplies  the  muscles  of  expression,  and  by  its  communi- 
cation with   the  vagus   both   comfort  and   distress   in   the   stomach  are  facially 
expressed. 

PHYSIOLOGICAL  REASONS  FOR  THE    NUMEROUS    COMMUNICATIONS  OF  THE  VAGUS 

NERVE. 

1 .  With  the  spinal  accessory  nerve.      The  spinal  part  of  the  spinal   accessory 
nerve  is  distributed  to  the  sterno-cleido-mastoid  andtrapezius  muscles,  and  assists 
in  forming  the  cervical  plexus.      It  will  be  remembered  that  the  mission  of  the 
cervical  plexus  is  to  supply  the  diaphragm  and  certain  muscles  of  forced  respira- 
tion, as  well  as  the  depressor  muscles  of  the  hyoid  bone.      (Page  73.)     'Now,  the 
accessory  part  of  the  spinal  accessory  nerve   supplies  the  muscles  of  the  soft 
palate.     Thus,  by  the  communication   between  the  vagus  and  the  spinal  acces- 
sory, harmony  is  established  between  the  muscles  that  rhythmically  enlarge  and 
reduce  the  size  of  the  thorax,  and  the   lungs  that  occupy  this  thorax,  and  by 
their  rhythmic  movements  carry  on  vocal  and  respiratory  processes. 

2.  I Vith  the  petrous  ganglion  of  the  glosso-pharyngcal  or  ninth  cranial  nerve. 
This  nerve  has  a  distribution  as  follows  :   (i)  To  the  tongue  ;  (2)  to  the  pharynx 
via  the  pharyngeal  plexus  ;  (3)  to  the  middle  ear,  Eustachian  tube,  and  mastoid 
cells  via  the  tympanic  plexus  ;  (4)  to  the  parotid  gland  via  its   small  superficial 
petrosal   branch  and  the  otic  ganglion  ;  (5)  to  the  facial  nerve  ;  (6)  to  the  sympa- 


418 


PRACTICAL   ANATOMY. 


thetic  nerve.  In  the  communications,  then,  between  the  pneumogastric  and  the 
glosso-pharyngeal  nerve,  we  see  the  connecting  link  between  a  mechanism 
pumping  air,  under  the  direction  of  the  vagus,  and  a  territory  to  be  constantly 


he  B1^  Pair  of  Nerves 

comprising  the 
9*.h  or  G I os so-  pharyngeal 
10V  or  Pneumogastnc, 
.  1 1  l.h  or  Spinal  Accessory. 


Terminal  Brs 

,  fivm  Tetteri  Com/undofAnntomij. 

IK;.   293. — EIGHTH  J'AIR  UK  CRANIAL  NERVES. 

i.  Jugular  ganglion  of  ninth  nerve.     2.  Petrous  ganglion  of  ninth  nerVe.     3.  Ganglion  of  the  vagus  root. 

4.   Ganglion  of  the  vagus  trunk.      5.    Medullary   part  of  eleventh   nerve.      6.   Spinal  part  of  eleventh 

nerve.      7.   Superior  cardiac   branch  joining  cardiac  of  sympathetic.      8.    Subclavian   artery,  mi  right 

tide,  arch  of  the  aorta,  on  lefi  side  <>f  the  l><>dy.     <>.   Koramen  magnum,  receiving  spinal  par)  of  the 

spinal  arct^-ory.       IO.   Jugular  l.-iainrn  ,  transmitting  all  tlircc  nerves;  also  (ailed  the  foramen  laeeium 

pdsterius.     ii.   Branches  to  hypoglossal,  sympathetic,  cervical  nerves.     12.  Olivary  body  (in  broken 

line). 

ventilated — the  middle  ear  and  Kustachian  tube,  a  territory  whose  delicate 
structures  might  be  invparably  (lania-cd,  \vrre  not  the  sensor)'  sentinel,  the 
tympanic  plexus,  thnv  i<>  ri'L'.ul.itf  the  ingress  and  egress  of  air.  And  note,  too, 


THE  BACK.  419 

the  expression  of  anguish  on  the  patient's  face  when  the  middle  ear  is  the  seat  of 
pain  ;  an  expression  determined  by  the  auricular  communicating  branch  of  the 
ninth  nerve  with  the  seventh  or  facial  nerve,  and  also  with  the  pneumogastric 
nerve,  as  represented  in  figure  293. 

3.  Wit  I i  the  Jiypoglossal  nerve,  by  which   the   movements  of  the   tongue  are 
harmonized  with  both  deglutition  and  vocal  action. 

4.  WitJi    the  sympathetic   nerve,  by  which  the  action  of  the  heart  and  lungs 
may  be  brought  into  harmony  with  their  environment. 

The  physiological  communications  of  the  vagus  nerve  are  : 

1.  With  the  spinal  accessory  nerve. 

2.  With  the  glosso-pharyngeal  nerve. 

3.  With  the  hypoglossal  nerve. 

4.  With  the  sympathetic  nerve. 

5.  With  the  first  and  second  cervicals. 

6.  With  the  facial  or  seventh  cranial  nerve. 

This  communication  is  for  the  purpose  of  harmonizing  respiration  and  the 
ingestion  of  food,  in  their  broadest  terms,  in  consonance  with  a  conservative  and 
aesthetic  adjustment  of  inner  to  outer  relations. 

Name  the  brancJics  of  the  vagus  nerve. 

1.  A  recurrent  branch  to  the  dura  mater. 

2.  The  auricular  branch,  given  off  from  the  ganglion  of  the  root,  is  joined  by 
a  branch   of  the  petrous  ganglion  of  the  glosso-pharyngeal.      (Fig.  293.)     This 
branch  divides  into  two  :  one  communicates  with  the  posterior  auricular  branch 
of  the  facial,  the  other  joins  the  facial  nerve  in  its  canal.      The  auricular  branch 
of  the  tenth  cranial  nerve  is  called  Arnold's  nerve. 

3.  The  pharyngeal  is  the  prime  motor  nerve  of  the  pharynx.     It  unites  with 
the  glosso-pharyngeal,  superior  laryngeal,  and  sympathetic  branches  to  form  the 
pharyngeal  plexus.      The  principal  fibres  of  the  pharyngeal  branch  of  the  pneumo- 
gastric are  derived  from  the  accessory  part  of  the  spinal  accessory  nerve. 

4.  The  superior  laryngeal  nerve  is  the  nerve  of  sensation  to  the  mucous  mem- 
brane of  the  larynx,  and  of  motion  to  the  crico-thyroid  muscle. 

5.  The  inferior  laryngeal  nerve  is  the  motor  nerve  to  all  the  intrinsic  muscles 
of  the  larynx  except  the  crico-thyroid.      This  is  also  called  the  recurrent  laryn- 
geal. 

6.  The  cervical  cardiac  branches  communicate  with  the  sympathetic,  and  pass 
to  the  superficial  and  deep  cardiac  plexuses. 

7.  The  thoracic  cardiac   branch  has  a  double  origin  :  (i)  From  the  trunk  of 
the  vagus  ;   (2)  from  the  recurrent  laryngeal  nerve.     They  are  distributed  to  the 
cardiac  plexus. 

8.  The  anterior  pulmonary  branches  unite  with  the  sympathetic  to  form  the 
anterior  pulmonary  plexus,  which  is  found  on  the  front  of  the  root  of  the  lung. 

9.  The  posterior  pulmonary  branches   unite  with   sympathetic  nerves  to  form 
the  posterior  pulmonary  plexus.     This  is  larger  than  the  preceding,  and  found  on 
the  posterior  part  of  the  root  of  the  lung.     (Fig.  151.) 

10.  The   cesophageal   plexus   supplies  the  oesophagus  and  pericardium.      It  is 
formed  by  the  union  of  branches   from   both  the  right  and   left  pneumogastric 
nerves.     The  plexus  is  also  called  the  plexus  guise,  because  gula  means  gullet. 

1 1.  The  terminal  branches  are  the  gastric.      The  branches  from  the  left  vagus 
supply  the   anterior,  those  from  the  right  the  posterior,  surface  of  the   stomach. 
They  unite  with    the  sympathetics    and  assist  also  in  forming  the   splenic  and 
hepatic  plexuses. 

Describe  tJie  spinal  accessory  nerve. 

This  is  the  eleventh  cranial  nerve.  It  leaves  the  cranium  by  the  jugular 
foramen  with  the  ninth  and  tenth  nerves  and  the  internal  jugular  vein.  It  has  : 


420 


PR  A  CTICAL   ANA  TO  MY. 


(i)  A  spinal  part  and  (2)  an  accessory  or  internal  part.  The  spinal  part  you 
will  trace  to  the  trapezius  and  sterno-mastoid  muscles.  The  accessor}'  part 
passes  forward  to  the  superior  laryngeal  nerve  and  pharyngeal  plexus. 

Describe  tlic  hypoglossal  or  twelfth  nerve. 

This  is  the  motor  nerve  of  the  tongue.  It  leaves  the  cranium  by  the  anterior 
condyloid  foramen.  It  supplies  the  depressor  muscles  of  the  hyoid  bone  in 
association  with  the  first  three  cervical  nerves.  It  communicates  with  the  vagus, 
lingual,  sympathetic,  and  upper  three  cervical  nerves. 


ARTICULATIONS.— LIGAMENTS. 


1 .  WJiat  is  an  articulation  ? 

Union  of  bone  to  bone,  bone  to  cartilage,  or  cartilage  to  cartilage,  by  means  of 
modified  periosteum  called  ligaments. 

2.  What  are  some  of  the  ends  subserved  by  articulations  / 

Stability,  as  in  the  joints  of  the  cranium  ;  motility,  as  in  the  extremities  ; 
semistability,  as  in  the  pelvis  and  vertebral  column. 

3 .  Name  and  indicate  the  function  of  the  structures  found  in  a  typical  articula- 
tion for  motility. 

(i)  There  is  bone  for  strength  and  solidity ;  (2)  a  shell  or  covering  of  bone, 
free  from  vessels  and  nerves,  adapted  to  bear  pressure  ;  (3)  a  highly  polished 
articular  cartilage  to  confer  elasticity  and  reduce  friction  ;  (4)  a  capsular  ligament, 
of  periosteal  derivation,  attached  above  and  below  the  joint  to  the  bones  party  to 
the  articulation  ;  (5)  a  synovial  membrane,  with  its  articular  vessels  and  nerves, 
closely  investing  the  interior  of  the  capsule,  for  the  secretion  of  synovia. 

4.  Name  the  structures  found  in  an  articulation  intended  for  stability. 

Bones  with  variously  shaped  edges,  whose  union  in  the  very  young  is  legal- 
ized by  periosteum  called  sutural  ligament. 

5.  Name  structures  found  in  an  articulation  wlicrc  semistability  is  to  be  attained. 
Bony   surfaces   firmly   united  by  discs  of  cartilage,    which  admit   of  slight 

motion,  and  under  certain  physiological  conditions — as  pregnancy — develop  par- 
tial synovial  membrane. 

6.  Are  there  any  technical  terms  by  zvhich  tlie  artiadations,  as  above  classed,  are 
designated  / 

SVNARTHROSIS  includes  all  immovable  articulations  where  bone  is  joined  to 
bone  by  variously  shaped  borders,  as  toothed,  grooved,  scaled,  sawlike,  and  seam- 
like. 

AMPHIARTHROSIS  includes  all  articulations  in  which  bone  is  firmly  united  to 
bone  by  cartilage,  with  slight  movement, — as  in  the  pelvis  and  vertebral  column, — 
and  a  spasmodic  production  of  synovia,  as  the  case  may  require  ;  as  in  pregnancy, 
this  may  be  the  case. 

DIARTHROSIS  includes  all  articulations  with  perfect  capsules,  free  movement, 
and  constant  production  of  synovia. 

7.  Does  the  degree  of  motion  vary  in  articulations  ? 

Yes ;  and  the  following  subdivisions  of  the  class  diarthrosis  express  the 
variety  or  kind  of  movement,  in  accordance  principally  with  the  degree  of  motion, 
as  determine'd  by  the  shape  of  the  articular  surfaces  :  (i)  Enarthrosis,  or  ball- 
and-socket  variety,  in  which  there  is  movement  in  four  modified  angular  direc- 
tions. Examples  of  this  are  seen  in  the  hip,  shoulder,  and  carpo-metacarpal 
articulation  of  the  thumb.  (2)  Condylarthrosis,  in  which  free  movement,  as  in  the 
ball-and-socket  articulation,  is  inhibited.  Instance,  the  temporo-maxillary,  occi- 
pito-atlantal,  radio-carpal,  metacarpo-phalangeal,  and  metatarso-phalangeal  joints. 
In  each,  as  you  may  demonstrate  on  yourselves,  there  is  free  movement — as 
flexion  and  extension — in  two  directions,  but  very  limited  movement  from  side 

421 


422  PRACTICAL  ANATOMY. 

to  side.  Observe  the  free  movement  of  the  fingers  on  the  metacarpals  forward 
and  backward,  and  the  limited  movement  from  side  to  side.  The  movement  of 
lower  jaw  is  the  same.  We  can  see  plainly  that  this  variety  of  joint  is  a  com- 
promise between  ball-and-socket  and  the  hinge -joint.  (3)  Ginglymus,  or  hinge- 
joint  t  in  which  there  is  free  movement  in  two  directions,  as  in  the  elbow,  knee, 
ankle,  and  interphalangeals  of  all  the  digits  of  both  feet  and  hands.  In  these 
articulations  note  the  impossibility  of  lateral  movement  without  violence  ;  note 
the  intermediate  position  between  this  variety  and  the  ball-and-socket  variety, 
occupied  by  the  preceding  condylarthrosis  subdivision.  (4)  Lateral  ginglymns 
is  a  term  used  to  express  a  subdivision  of  movable  joint  which  differs  from  the 
hinge  movement  in  no  essential,  except  in  the  direction  of  motion.  The  supe- 
rior and  inferior  radio-ulnar  articulations  and  the  atlanto-oclontoid  belong  to 
this  subdivision.  (5)  Arthrodia  includes  the  simplest  subdivisions  of  all  the 
movable  articulations.  In  this  kind  the  surfaces  are  plane,  or  nearly  so.  The 
movements  are  limited,  by  virtue  of  the  strong  and  unyielding  nature  of  the  liga- 
ments, which  represent  the  lowest  organized  variety  of  capsular  ligament.  Kx- 
amples  of  this  subdivision  are  in  the  carpal  and  tarsal  articulations  ;  between 
the  metacarpals  and  metatarsals  ;  in  the  articular  processes  of  the  vertebrae  ;  in 
the  costo-transverse  and  interchondral  articulations. 

I  desire  you  to  dissect  and  study  the  movable  articulations — the  diarthroses— 
according  to  the  following  outline  : 

1 .  Give  the  name  of  the  class — diarthrosis,  for  example. 

2.  Give  the  name  of  the  subdivisions  of  the  class. 

3.  Give  the  technical  name  of  the  locality. 

4.  Give  the  osteological  units  in  the  joint. 

5.  Give  subdivisional  parts  of  osteological  units. 

6.  Name  the  articular  surfaces  according  to  the  rule. 

7.  Give  the  basis  of  a  movable  joint — a  capsule. 

8.  Give  the  local  subdivisions  of  the  capsule. 

9.  Name  the  strengthening  bands  of  the  capsule,  if  any. 

10.  Name  the  incorporated  tendons  of  obsolete  muscles,  if  any. 

1 1.  Name  the  bony  limitations  of  movements  of  the  joint. 

12.  Name  the  nerve-supply  and  blood-supply  of  the  joint. 

13.  Name  the  ligamentous  muscles  of  the  joint. 

Let  us  review  now  the  above  outline,  and  understand  its  specific  scope. 

1.  There  are  five   subdivisions   of  the   class   diarthrosis.      (Page  424.)      Ky 
examining  the  articulation,  you   find  movement  in  two  directions.      Your  entry 
should  read  :  Class,  diarthrosis  ;    Subdivision,  ginglymus. 

2.  Let  us  assume  the  particular  joint  is  the  elbow  :  then  the  technical  name- 
is  humero-radio-ulnar  articulation  ;  the  common  name,  elbow-joint. 

3.  The  osteological  units  in  this  joint  are  the  humerus,  radius,  and  ulna. 

4.  The  subdivisional  parts  of  the  osteological  units  are  the  outer  and  inner 
humeral  condyles,  radial   head   of  humerus,  head   of  radius,  olecranon  process 
of  ulna,  coronoid  process  of  ulna,  greater  sigmoid  cavity  of  ulna. 

5.  Articular  surfaces  should  take  the  name  of  the  occupant.     Then  in  this 
joint  we  find  the  radial  and  ulnar  surfaces  of  the  humerus  ;  the  humeral  surfaces 
of  the  ratlins  and  ulna.      The  ulnar  surface  of  the  humerus  is  called  technical!}'  the 
trochlear    or  pulley   surface  ;    the  radial  surface   of  the   humerus    is   called  the 
capitcllum,  or  link-  head. 

6.  The  basic  principle  in  every  movable  joint   is  a  capsule  derived  from  peri- 
osteum, linrd  by  a  more  or  less  extrusive  synovial  membrane. 

7.  The  subdivisions  of  the  capsule  are  anterior,  posterior,  internal  lateral,  ami 
external  ligaments.      A  complete  capsule  is  equal  to  the  sum  of  its  subdivisional 
parts.      The   usage   by  which    capsules    are  thus  subdivided  is  a  useless   (except 


ARTICULA  TIONS.  —LIGAMENTS.  4  2  3 

for  locating  lacerations  in  rare  instances)  as  well  as  an  arbitrary  practice.  There 
is  no  well-defined  line  of  demarcation  between  a  lateral  and  an  anterior  part  of 
a  capsule,  as  the  student  may  expect  to  find,  since  transitions  in  anatomy  are 
easy  and  gradual. 

8.  Strengthening  or  accessory  bands  are  derived  either  from  the  deep  fascia 
or  from  the  aponeurosis  of  a  muscle  crossing  a  joint. 

9.  By  incorporation  of  tendons  in  a  capsule,  the  capsule  becomes  stronger 
where  the  incorporation  occurs.      Growth  is  the  correlative  of  function,  you  will 
remember  ;    now,  if  from  change  in  environment  an  animal  acquire  altered  body 
movements,  a  muscle  may  migrate  from  its  primitive  insertion  below  a  joint  to 
an  acquired  insertion  above  a  joint.      Loss  of  function  entails  loss  of  specific  char- 
acter ;  in  this  case  loss  of  specific  character — that  is,  loss  of  muscular  element — 
leaves   only  the  connective-tissue  framework  crossing  the  joint.       The   muscle 
migrated,  the  tendon  became  divorced,  and  by  vigorous  retrogression  of  muscle, 
a  band  of  connective  tissue  remains  which  strengthens  the  capsule  ;  the  original 
tendon  became   incorporated  with   the   capsule.       The   divorced  tendon   of  the 
adductor  magnus  obtains  as  the  internal  lateral  ligament  of  the  knee-joint  ;  that 
of  the  peroneus  longus  as  the  external  lateral  ligament.     The  coraco-humeral 
ligament  is  the  divorced  tendon  of  the   minor  pectoral  muscle.      The  greater 
sacro-sciatic  ligament  is  the  divorced  tendon  of  the  biceps  femoris.     The  liga- 
mentum  teres  in   the  hip-joint  is  said  by   Morris  to  be  in  all   probability  the 
divorced  tendon  of  the  pectineus  muscle. 

10.  The  movements  of  joints  are  often  limited  by  bone.      Note  should  be 
taken   of  these  physiological  limitations  on  the  cadaver  when  you  dissect  liga- 
ments. 

1 1.  Ligamentous  muscles  to  a  joint  are  such  muscles  as  cross  a  joint.     The 
biceps,  brachialis  anticus,  triceps,  and  all   the  muscles  getting  origin  from  the 

'humeral  condyles  are  ligamentous  in  their  action  to  the  elbow-joint.  Muscles 
— as  the  rectus  femoris  and  the  sartorius — may  be  ligamentous  to  more  than  one 
joint.  Ligamentous  muscles  are  also  called  the  elastic  ligaments  of  a  joint. 

12.  Note  the  entrance  of  nerves  and  vessels  that  supply  the  synovial  mem- 
brane.     Such  structures  are  designated  articular.     In  this  connection  refer  to 
Hilton's  law  governing  articular  nerves.      This  law  is  given  in  the  introductory 
chapter  of  this  book  on  page  19. 

13.  Finally,  having  found  in  the  make-up  of  movable  joints  bone,  articular 
lamella,   cartilage,   ligament,   tendon,  muscle,    synovial    membrane,    nerve,    and 
blood-vessels,  be  able  to  classify  these  structures  histologically,  according  to  the 
outline  given  in  the  beginning  of  this  work  under  caption  of  anatomical  tissues. 
The  plan  just  outlined  for  your  guidance  will  not  only  give  you  a  thorough  un- 
derstanding of  the  ligaments,  but  will  refresh  your  memory  on  those  very  prac- 
tical  points  you  will  so  much  need  in  your  subsequent  medical  studies,  both  as 
students  and  as  practitioners  of  medicine. 

Whenever  you  are  in  doubt  as  to   the  name  of  a  particular  subdivision  of  a 
class,  consult  the  following  table,  taken  from  Morris  : 


TABLE  OF  THE  VARIOUS  CLASSES  OF  JOINTS. 

Class.  Examples. 

I.   Synarthrosis 

(a)  True  sutures Lambdoid,  sagittal,  coronal. 

(^)  False  sutures Internasal.     Intermaxillary.     Costo-chondral. 

(c)  Grooved  sutures Vomer  and  rostrum  of  sphenoid. 

II.  Amphiarthrosis Bodies  of  vertebras.     Symphysis  pubis,  sacro- 

iliac,  sacro-coccygeal. 


424 


PRACTICAL  ANATOMY. 


TABLE  OF  THE  VARIOUS  CLASSES  OF  JOINTS. — (Continued.') 


Class. 
III.  Diarthrosis 

(a)  Enarthrosis  .    .    . 
(b}  Condylarthrosis    . 


(c)  Ginglymus  or  Trochlearthrosis    . 

(d)  Trochoides  or  Lateral  Ginglymus 

(<?)  Arthrodia : 

(i)  Simple 


(2)  Saddle-shaped 


Examples. 

Shoulder.     Hip.     Astragalo-scaphoid. 

Temporo-mandibular.  Occipito-atlantal. 
Radio-carpal.  Metacarpo  -  phalangeal. 
Metatarso-phalangeal. 

Elbow.  Ankle.  Knee.  Interphalangeal  of 
fingers  and  toes. 

Atlanto-odontoid.  Superior  Radio-ulnar.  In- 
ferior Radio-ulnar. 

Lateral  atlanto-axoidean.  The  joints  between 
the  articular  processes  of  the  vertebras,  costo- 
transverse,  and  interchondral.  Acromio- 
clavicular.  Carpal.  Carpo-metacarpal  of 
four  fingers.  Intermetacarpal.  Tar  sal. 
Tarso-metatarsal.  Intermetatarsal.  Cal- 
caneo-astragaloid.  Superior  and  inferior 
tibio-fibular. 

Sterno-costo-clavicular.  Carpo-metacarpal  of 
thumb.  Calcaneo-cuboid. 


The  following  is  a  list  of  the  principal  articulations  of  the  immovable  class — 
synarthrosis.      Let  the  student  locate  these  joints  on  the  skull  : 


COMPOUND. 

BASE. 

ADJUNCT. 

I.  Temporo-parietal. 

Temporal. 

Parietal. 

2.  Interparietal. 

Parietal. 

Parietal. 

3.  Pronto-parietal. 

Frontal. 

Parietal. 

4.  Occipito-parietal. 

Occipital. 

Parietal. 

5.  Masto-parietal. 

Mastoid. 

Parietal. 

6.  Squamo-parietal. 

Squamosa. 

Parietal. 

7.  Occipito-sphenoidal. 

Occipital.                         Sphenoid. 

8.  Occipito-temporal. 

Occipital.                         Temporal. 

9.  Spheno-temporal. 

Sphenoid. 

Temporal. 

10.  Spheno-frontal. 

Sphenoid. 

Frontal. 

n.  Spheno-ethmoidal. 

Sphenoid.                        Ethmoid. 

12.  Fronto-ethmoidal. 

Frontal.                           Ethmoid. 

13.  Fronto-maxillary. 

Frontal.                           Maxillary. 

14.  Fronto-nasal. 

Frontal.                           Nasal. 

15.  Fronto-lachrymal. 

Frontal.                           Lachrymal. 

1  6.  Fronto-malar. 

Frontal. 

Malar. 

17.  Lachrymo-ethmoidal. 

Lachrymal. 

Ethmoid. 

18.  Naso-maxillary. 

Nasal. 

Maxillary. 

19.  Malo-maxillary. 

Malar. 

Maxillary. 

20.  Costo-chondral. 

Costal  (Rib). 

Chondrum. 

The  following  are  the  members  of  the  group  of  amphiarthrosis  articulations. 
Their  number  is  small.  Remember,  the  opposed  bony  surfaces  are  united  by 
discs  of  cartilage;  there  is  slight  movement,  clue  principally  to  the  elastic  nature 
of  the  discs  of  cartilage.  A  partial  synovial  membrane  may  be  developed  during 
pivgnancy  : 

1.  The  intervertebral  or  intercentral  articulations. 

2.  The  sacro-iliac  synchrondrosis. 

3.  The  sacro-coccygeal  articulation. 

4.  The  intercoccygeal  articulations. 

5.  The  interpubic  articulation — symphysis  pubis. 


AR  TICULA  TIONS.  —LIGAMENTS. 


425 


TEMPORO-MANDIBULAR  ARTICULATION. 

1.  Locate  and  give  the  synonym  for  temporo-mandibular  articulation. 

This  articulation  is  between  the  glenoid  fossa  of  the  temporal  bone  and  the 
condyle  of  the  mandible  or  lower  jaw-bone.  It  is  also  called  temporo-maxillary 
articulation. 

2.  Name  some  of  the  conditions  that  make  this  articulation  one  of  practical  im- 
portance in  medicine  and  surgery. 

Passing  over  the  part  this  joint  plays  in  the  mastication  of  food,  since  this  is 
too  well  understood  by  the  student  to  need  explanation,  we  may  mention  the 
following  :  («)  Temporo-mandibular  fixity  may  occur  in  cases  of  exposed  tooth- 
pulp.  The  nerve  supplying  the  pulp,  the  trigeminus,  also  supplies  the  muscles 
of  mastication.  Here,  then,  we  have  a  moto -sensory  reflex  circuit.  The  power- 
ful contraction  of  the  muscles  will  cease  on  the  administration  of  an  anaesthetic. 


Interarticular  flbro- 

cartilage 

SECTION  THROUGH  CONOYLE 
Posterior  portion  of 
capsule 


Spheno-mandibul 


Stylo-mandibular  ligament 


FIG.  294. — VERTICAL  SECTION  THROUGH  THE  CONDYLE  OF  JAW  TO  SHOW  THE  Two  SYNOVIAL 

SACS    AND    THE    INTERARTICULAR    FlBRO-CARTILAGE. 


I  once  saw  a  case  of  fixed  jaw  produced  by  a  bug  in  the  ear.  Here  was  the 
same  moto-sensory  reflex  circuit.  The  same  nerve  that  supplies  the  muscles  of 
mastication — the  fifth  cranial — also  supplies  the  auditory  canal  through  its  auriculo- 
temporal  branch.  In  this  case  no  ordinary  traction  would  open  the  mouth.  An 
elderly  lady  suggested  the  curative  property  of  warm  salt-water  in  "lock-jaw." 
The  ear  was  filled  with  water,  the  bug  came  out,  and  instantly  the  patient  could 
open  her  mouth,  (b)  The  condyle  glides  forward  onto  the  eminentia  articularis 
(Fig.  58)  when  the  mouth  is  open.  In  this  position  a  dislocation  may  occur. 
The  condyle  is  deeply  lodged  in  the  glenoid  cavity  when  the  mouth  is  closed. 
In  this  position  a  blow  on  the  chin  may  fracture  the  tympanic  wall  ;  while  a 
blow  on  the  angle  of  the  jaw  may  break  the  thin  dome  of  the  glenoid,  and 
produce  injury  to  the  brain. 

3.   Hoiv  is  the  glenoid  cavity  limited  in  front  and  beltind  / 

Anteriorly,  by  the  eminentia  articularis  ;  posteriorly,  by  the  Glaserian  fissure 
and  the  post-glenoid  tubercle. 
28 


426  PRACTICAL   ANATOMY. 

4.  H<nv  many  synovial  cavities  has  the  tcmporo-mandibular  articulation  and 
/low  are  they  produced  ? 

It  has  two  ;  they  are  produced  by  interposition  of  the  interarticular  fibro- 
cartilage.  The  periphery  of  this  disc  is  attached  to  the  capsule.  (Fig.  294.) 

5.  Explain  the  use  of  this  interarticular  cartilage. 

When  the  mouth  is  opened,  the  condyle  of  the  mandible  slides  forward  onto 
the  eminentia  articularis,  in  the  concave  cup  of  the  articular  cartilage  ;  when  the 
mouth  is  shut,  the  condyle  and  cartilage  recede  into  the  glenoid.  (Fig.  59.) 

6.  By  what  are  the  condyle  and  cartilage  drawn  forward  f 

By  the  external  pterygoid  muscle,  a  portion  of  the  muscle  being  inserted  into 
the  cartilage  as  well  as  into  the  condyle.  (Fig.  58.) 


DISSECTION. 

It  is  to  be  hoped  that  the  foregoing  has  prepared  the  student  to  begin  an 
intelligent  dissection  of  the  articulations. 

TEMPORO-MANDIBULAR  ARTICULATION. 

1 .  Class. — Diarthrosis, because  there  is  free  motion. 

2.  Subdivision. — Condylarthrosis,  because  axial  rotation  is  absent. 

3.  Osteological  Units. — Mandible  and  temporal  bone. 

4.  Subdivisional  Parts. — Condylar  process  and  glenoid  cavity. 

5.  Articular  Surfaces. — Condylar  of  temporal  ;  temporal  of  condyle. 

6.  Basis. — A  complete  capsule  lined  by  synovial  membrane. 

7.  Subdivisions. — Anterior,  posterior,  internal,  and  external  portions. 

8.  Accessories. — Spheno-mandibular,  stylo-mandibular,  fibro-cartilage. 

9.  Incorporation  of  Tendons. — None. 

10.  Limitations. — Articular  eminence,  post-glenoid  tubercle. 

1 1.  Ligamcntous  Muscles. — Internal  and  external  pterygoids,masseter. 

12.  Nerve-supply. — Masseteric  and  auriculo-temporal  of  the  fifth. 

13.  Blood-supply. — Temporal,  middle  meningeal,  ascending  pharyngeal. 

1.  Name  the  osteological parts  concerned  in  t/iis  articulation. 

(i)  The  zygomatic  arch  ;  (2)  the  spine  of  the  sphenoid  ;  (3)  the  styloid  pro- 
cess of  the  temporal  bone  ;  (4)  the  lingula  of  the  mandible  ;  (5)  the  eminentia 
articularis  of  the  temporal  bone  ;  (6)  the  post-glenoid  tubercle  and  tympanic  plate 
of  the  temporal  bone  ;  (7)  the  Glaserian  fissure  of  the  temporal  bone. 

2.  Give  attachments  of  the  spheno-mandibular  ligament  as  you  find  them,  and 
tell  by  what  nerve  this  ligament  is  pierced. 

The  ligament  extends  from  the  spine  of  the  greater  wing  of  the  sphenoid  bone 
to  the  lingula  or  mandibular  spine,  and  is  perforated  by  the  mylo-hyoid  nerve. 

3.  Locate  and  give  attachments  of  tJic  stylo-mandibular  ligament. 

It  is  between  the  masseter  and  internal  pterygoid  muscles  ;  it  is  attached  to 
the  styloid  process  and  to  the  angle  of  the  mandible.  (Fig.  296.) 

SHOULDER-JOINT. 

1.  Class. — Diarthrosis,  because  of  free  motion. 

2.  Subdivision. — Knarthrodia — an^nl.ir  movements  and  axial  rotation. 

3.  I'eclinienl  \,ime. —  I  lutnero-scapular  ;  common  name,  shoulder-joint. 

4.  Osteological  ('nits. — Humerus  and  scapula. 


ARTJCULA  TIONS.  —LIGAMENTS. 


427 


5.  Subdivisional  Parts. — Head  of  humerus,  glenoid  of  scapula. 

6.  Articular  Surfaces. — Humeral  of  scapula,  scapular  of  humerus. 

7.  Basis. — A  complete  capsule  lined  by  synovial  membrane. 

8.  Subdivisions. — Not  subdivided  for  description. 

9.  Strengthening  Bands. — Three  gleno-humeral  ligaments. 


,  ^iiiu       External  portion 
of  capsule 


Stylo-mandibular  ligament 


Fit;.  295. — EXTERNAL  VIEW  OF  TEMPORO-MANDIBULAR  JOINT. 


Internal  portion 
of  capsule 


Spheno-mandibular 
ligament 


Btylo-maudibular 
ligament 


FIG.  296. — INTERNAL  VIEW  OF  TEMPORO-MANDIBULAR  JOINT. 


10.  Incorporated  tendon  of  pectoralis  minor  in  primitive  man. 

11.  Limitations. — Clavicle,  acromion,  and  coracoid  process. 

12.  Nerve-supply. — Subscapular,  circumflex,  suprascapular. 

13.  Blood-supply. — Circumflex,  subscapular,  dorsalis  scapulae,  axillary. 

14.  Ligamcntous  Muscles. — (i)  Biceps;   (2)  triceps;   (3)  supraspinatus  ;  (4) 


428 


PKA  CTICAL  ANA  TOM ) '. 


infraspinatus  ;  (5)  subscapularis  ;   (6)  teres  minor  ;   (7)  teres  major  ;  (8)  latissimus 
dorsi  ;  (9)  coraco-brachialis  ;  (10)  pectoralis  major  ;  (i  i)  deltoid. 

1 .  Name  the  osteological  parts  concerned  in  this  articulation  in  any  manner. 

(i)  The  articular  surface  of  the  humeral  head;  (2)  the  glenoid  cavity  of  the 
scapular  head  ;  (3)  the  anatomical  neck  of  the  humerus  ;  (4)  the  anatomical  neck 
of  the  scapula  ;  (5)  the  greater  tuberosity  with  its  three  facets  ;  (6)  the  lesser 
tuberosity  with  one  facet  ;  (7)  the  surgical  neck  of  the  humerus  ;  (8)  the  surgi- 
cal neck  of  the  scapula  ;  (9)  the  humeral  bicipital  groove  and  its  lips  ;  (10)  the 
supraglenoid  tubercle — bicipital ;  (i  i)  the  infraglenoid  tubercle — tricipital  ;  (12) 
the  scapular  notch  and  foramen;  (13)  the  suprascapular  notch  and  foramen  ; 
(14)  the  fourth  scapular  angle  ;  (15)  the  acromion  process  of  scapula  ;  (16)  the 
coracoid  process  of  the  scapula. 

2.  Give  the  morphology  of  the  coraco-Jutmeral  ligament. 


Trapezoid  ligament 


Tendon  of  subscapularis  muscle 


Capsule  of  the  acromio-elavicular 
joint 

Coraco-acromial  ligament 
Coraco-humeral  ligament 


Transverse  humeral  ligament 


Tendon  of  biceps 


FIG.  297. — OUTER  VIEW  OK  THK  SHOULDER-JOINT,  SHOWING  THI.  CORACO-HUMERAL  AND 
TRANSVERSE  HUMERAL  LIGAMENTS. 


It  is  the  divorced  tendon  of  the  pectoralis  minor  muscle,  which  in  primitive 
man  was  inserted  into  the  lesser  tuberosity  of  the  humerus. 

3.  By  ichat  is  tlie  capsule  of  the  shoulder-joint  lined  / 

By  synovial  membrane.  This  membrane  is  also  reflected  onto  the  long  head 
of  the  biceps  muscle  in  its  transit  of  the  cavity. 

4.  \Vliere  is  tlic  transverse  /mineral  ligament,  and  -<chat  is  its  function  / 

It  stretches  from  greater  to  lesser  tuberosity,  converting  the  bicipital  groove 
into  a  canal  for  the  lodgment  of  the  long  tendon  of  origin  of  the  biceps  muscle. 
The  canal  is  lined  by  a  vaginal  synovial  membrane. 

5.  ]\  'hat  is  (lie  g/enoid  ligament  / 

A  circumferential  rim  of  cartilage  whose  function  seems  to  be  to  deepen  the 
cavity  for  the  head  of  tin:  hiimerus.  It  is  attaehed  to  the  capsule,  and  also  to  the 
margin  of  the  glenoid  cavity.  It  is  also  continuous  with  the  long  head  of  the 
biceps  muscle. 


ARTICULA  TIONS.— LIGAMENTS. 


429 


6.  Through  what  osteological  points  'would  a  fracture  of  the  surgical  neck  of  tlic 
scapula  pass  ? 

(i)  Through  the  suprascapular  notch  ;  (2)  through  the  scapular  notch  ;  (3) 
through  the  fourth  scapular  angle  or  the  deepest  part  of  the  subscapular  fossa. 

Tell  where  tJie  ligaments  are  found  by  which  the  scapula  and  clavicle  arc  held 
together. 

THE  SCAPULO-CLAVICULAR  UNION. 

1.  Between  the  acromion  process  of  the  scapula  and  the  clavicle. 

2.  Between  the  coracoid  process  and  the  clavicle. 

3.  Between  certain  given  parts  of  the  scapula  alone.      (Fig.  298.) 

Transverse  ligament 


Conoid  ligament 


Acromio-clavioular 
ligament 


Tendon  of  infra- 
spinatus  and  teres 
minor 

Inferior  transverse 
or  spino-glenoid 
ligament 
Capsule  of  shoulder 


FIG.  298. — POSTERIOR  VIEW  OF  THE  SHOULDER-JOINT,  SHOWING  ALSO  THE  ACROMIO- 
CLAVICULAR  JOINT  AND  THE  PROPER  LIGAMENTS  OF  THE  SCAPULA. 


THE  ACROMIO-CLAVICULAR  ARTICULATION. 

1.  Class. — Diarthrosis,  because  of  capsule,  synovia,  and  motion. 

2.  Subdivision. — Arthrodia,  because  of  gliding,  simple  movement. 

3.  Technical  Name. — Acromio-clavicular  articulation. 

4.  Osteological  Units. — Clavicle  and  scapula. 

5.  Subdivisional  Parts. — Acromion  and  acromial  end  of  clavicle. 

6.  Articular  Surfaces. — Acromial  of  clavicle,  clavicular  of  acromion. 

7.  Basis. — A  capsule  lined  by  synovial  membrane. 
Subdivisions  of  Capsule. — Superior  and  inferior,  by  some  authors. 
Strengthening  Bands. — None.      Purely  periosteal. 
Incorporation  of  Tendons. — None. 

Limitation  of  Motion  by  Bone. — None. 
Ligaincntous  Muscles. — Deltoid  and  major  pectoral. 
Nerve-supply. — The  circumflex. 
14.  Blood-supply. — Circumflex,  acromio-thoracic. 


8 

9- 
10. 
1 1. 

12. 
13 


43° 


PRACTICAL   ANATOMY. 


1 .  Describe  tlic  acromion  process. 

It  is  a  projection  of  bone,  a  continuation  of  the  scapular  spine.  It  has  an 
upper  and  an  under  surface,  an  inner  and  an  outer  border,  and  a  tip.  Its  inner 
border  articulates  near  the  tip  with  the  clavicle.  Its  outer  border  gives  origin  to 
the  deltoid  muscle  in  part.  Its  upper  surface  is  occupied  by  the  insertion  of  the 
trapezius  muscle,  by  the  origin  of  the  deltoid,  and  by  a  subcutaneous  area  between 
the  two.  Its  under  surface  is  smooth  and  unoccupied.  (Fig.  240.) 

2.  Describe  the  interarticular  fibro-cartilage. 

When  present,  it  resembles  others  of  the  same  class  in  function  and  attach- 
ments. 


Conoid  ligament 


Transverse  scapular  ligament 


Trapezoid  ligament 


Coraco-acromial  ligament 


Short  head  of  biceps 
Subscapular  tendon 


Capsule  of  shoulder 


Long  tendon  of 
biceps 


FIG.  299. — ANTERIOR  VIEW  OF  SHOULDER,  SHOWING  ALSO  CORACO-CLAVICI'LAR  AND  CORACO- 
ACROMIAL  LIGAMENTS. 


THE   COR  AGO-CLAVICULAR   LIGAMENTS. 

Turn  the  clavicle  upward,  having  cut  the  same  through  the  middle  third,  an< 
you  will  see  a  strong  band  of  ligamentous  tissue  extending  from  the  clavicle  to 
the  coracoid  process.  This  consists  of  two  parts  :  an  anterior  and  outer  part,  called 
the  trapezoid  ligament ;  a  posterior  and  internal  portion,  called  the  conoid  liga- 
ment. The  action  of  these  ligaments  is  to  prevent  upward  dislocation  of  the 
acromial  end  of  the  clavicle  in  fracture  of  the  bone. 

The  intrinsic  ligaments  of  the  scapula  are  :  (i)  The  coraco-acromial ;  (2)  the 
transverse  scapular  (Fig.  299)  ;  (3)  the  inferior  transverse  scapular.  (Fig.  298.) 

The  coraco-acromial  extends  from  the  outer  border  of  the  coracoid  process 
by  a  broad  base  to  the  tip  of  the  acromion  process.  Under  it  you  will  find  the 
tendon  of  the  stipraspinatus  muscle  in  a  bed  of  fatty  connective  tissue. 

The  transverse  scapular  ligament  bridges  over  the  suprascapular  notch, 
converting  the  same  into  a  foramen,  terminating  externally  in  the  coracoid 
process.  On  the  ligament  lie  the  suprascapular  vessels  ;  beneath  the  ligament,  in 
the  foramen,  you  will  find  the  suprascapular  nerve.  (Fig.  299.) 


AR  TICULA  TIONS.  —LIGA  ME  NTS.  43 1 

The  inferior  scapular  ligament  extends  from  the  glenoid  margin  to  the 
spine.  Under  it  pass  the  infraspinatous  divisions  of  the  suprascapular  vessels 
and  nerves.  (Fig.  249.) 

THE  STERNO-CLAVICULAR  ARTICULATION. 

1.  Class. — Diarthrosis,  since  capsule  and  motion  are  present. 

2.  Subdivision. — Arthrodia — simple  gliding  articular  surfaces. 

3.  Technical  Name. — Sterno-clavicular  articulation. 

4.  Osteological  Units. — Sternum  and  clavicle. 

5.  Sub  divisional  Parts. — Manubrium  and  sternal  end  of  clavicle. 

6.  Articular  Surfaces. — Sternal  of  clavicle,  clavicular  of  sternum. 

7.  Basis. — A  capsule  lined  by  synovial  membrane. 

8.  Local  Subdivisions. — Should  be  none. 

9.  Strengthening  Bands. — None.     Periosteal  purely. 

10.  Incorporated  Tendons. — None. 

1 1.  Bony  Limitations. — Manubrium  and  first  rib. 

1 2.  Nerve-supply. — Brachial  plexus  by  nerve  to  subclavius. 

13.  Ligamentous  Muscles. — Subclavius  and  sterno-mastoid. 


Rhomboid 
ligament 
Anterior 
sterno- 
clavieular 
ligament 


FIG.  300. — ANTERIOR  VIEW  OF  STERNO-CLAVICULAR  JOINT. 

(The  capsule  is  cut  into  on  the  left  side  to  show  the  interarticular  fibro- cartilage  dividing  the  joint 

into  two  cavities.) 

1 .  Name  all  tlie  ligaments  of  this  articulation. 

The  capsular,  the  basis  of  the  joint.  The  interclavicular  binds  the  clavicles  to 
the  sternum.  The  costo-clavicular,  or  rhomboid.  The  interarticular  fibro- 
cartilage. 

2.  How  many  synovial  cavities  has  the  articulation  ? 

Two,  separated  from  each  other  by  the  interarticular  fibro-cartilage.  This 
cartilage  is  attached  to  the  capsule  like  others  of  its  class,  as  the  temporo-man- 
dibular  and  the  inconstant  acromio-clavicular  interarticular  fibro-cartilage. 

3.  In  practical  dissection,  when  yon  wish  to  remove  the  clavicle,  what  is  the  most 
difficult  structure  to  divide  ? 

The  costo-clavicular  ligament  binding  the  clavicle  very  firmly  to  the  first  rib. 

4.  What  muscle  do  you  find  under  the  clavicle,  and  what  is  its  surgical  impor- 
tance ? 

The  subclavius  muscle,  arising  in  front  of  the  costo-clavicular  ligament  from 
the  first  rib.  It  is  inserted  into  the  middle  third  of  the  clavicle  on  the  under  sur- 
face of  the  bone.  In  fracture  of  the  clavicle  in  the  middle  or  outer  third,  the 


43 2  PRACTICAL  ANATOMY. 

subclavius  depresses  the  inner  segment  of  the  bone,  while  the  weight  of  the  arm 
elevates  the  outer  fragment.  These  anatomical  facts  led  up  to  the  empiric  prac- 
tice of  elevating  the  elbow  and  adjusting  the  inner  to  the  outer  clavicular  frag- 
ments in  the  treatment  of  fracture  of  this  bone. 

ELBOW-JOINT. 

1.  Class. — Diarthrosis,  because  of  free  motion  and  a  capsule. 

2.  Subdivision. — Ginglymus,  because  of  motion  in  two  directions. 

3.  Technical  Name. — Humero-radio-ulnar  articulation. 

4.  Osteological  Units. — Humerus,  radius,  ulna. 

5.  Subdivisional  Parts. — Two  humeral  condyles,  a  radial  head,  an  olecranon 
process,  a  coronoid  process,  a  greater  sigmoid  cavity,  two  condylar  ridges,  an 
olecranon  fossa,  a  coronoid  fossa,  a  radial  fossa. 

6.  Radial  and  Ulnar  Articular  Surfaces  of  Humerus. — Humeral   surfaces  of 
radius  and  ulna.     The  ulnar  surface  of  the  humerus  is  called  the  trochlea.     The 
radial  head  of  the  humerus  is  called  the  capitellum. 

7.  Basis. — A  capsule  lined  by  synovial  membrane. 

8.  Local  Subdivisions. — Anterior,  posterior,  internal,  and  external. 

9.  Strengthening  Bands. — None. 

10.  Incorporated  Tendons. — None. 

1 1.  Bone  Limitations. — Olecranon  and  coronoid  processes,  humerus. 

12.  Nerve-supply. — Ulnar,  median,  musculo-cutaneous,  musculo-spiral. 

13.  Blood-supply. — From  the  anastomosis  about  the  joint. 

14.  Ligamentous  Muscles. — Biceps,  brachialis  anticus,   supinator   longus  or 
brachio-radialis  ;  triceps  and  anconeus  ;  pronator  radii  teres,  flexor  carpi  radialis, 
palmaris  longus,  flexor  sublimis  digitorum,  flexor  carpi  ulnaris  ;  supinator  brevis, 
extensor  carpi  radialis  longior,  extensor  carpi  radialis  brevior,  extensor  communis 
digitorum,  extensor  minimi  digiti,  extensor  carpi  ulnaris. 

Through  -what  ivould  a  fracture  immediately  above  the  condyles  pass  ? 
Through  the  external  and  internal  condylar  ridges,  through  the  olecranon, 
radial,  and  coronoid  fossae  of  the  humerus. 

SUPERIOR  RADIO-ULNAR  ARTICULATION. 

1.  Class. — Diarthrosis,  because  of  free  motion. 

2.  Subdivision. — Lateral  ginglymus,  motion  in  two  directions  only. 

3.  Technical  Name. — Superior  radio-ulnar  articulation. 

4.  Osteological  Units. — Radius  and  ulna. 

5.  Subdivisional  Parts. — Head  of  radius  and  lesser  sigmoid  of  ulna. 

6.  Articular  Surfaces. — Radial  of  ulna,  ulnar  surface  of  radius. 

7.  Basis. — An  orbicular  capsule  lined  by  synovial  membrane. 

8.  Local  Subdivisions  of  Capsule. — None. 

9.  Strengthening  Bands  of  the  Orbicular  C  'apsule. — None. 

10.  Incorporated  Tendons  of  Obsolete  Muscles. — None. 

11.  Bony  Limitations. — The  ulna  and  humerus. 

12.  Nerve-  and  Blood-supply. — Same  as  elbow-joint. 

13.  Ligamentous  Muscles. — Supinator  brevis  and  supinator  longus. 
Xdine  (lie  muscles  inserted  in  the  vicinity  of  this  articulation. 

The  biceps  into  the  bicipital  tuherosity  of  the  radius.  The  brachialis  anticus 
into  the  coronoid  process  of  the  ulna.  The  triceps  into  the  olecranon  process 
of  the  ulna. 

(i'i-<'C  tlic  origin  and  insertion  of  the  orbicular  ligament. 

It  describes  three-fourths  of  a  circle,  and  is  attached  to  the  anterior  and  pos- 
terior lips  of  the  lesser  sigmoid  cavity  of  the  ulna. 


A  R  T1CULA  TIONS.  —LIGAMENTS. 


433 


Locate  tlie  lesser  sig moid  cavity. 

It  is  on  the  outer  part  of  the  ulrfa,  at  the  junction  of  the  olecranon  and  coro- 
noid  processes  ;  it  is  limited  in  front  and  behind  by  the  anterior  and  posterior  lips 
of  the  cavity.  It  contains  the  head  of  the  radius.  It  is  covered  by  articular 
cartilage. 

THE   INTEROSSEOUS   MEMBRANE. 

This  you  will  see  extending  from  the  interosseous  ridge  of  the  ulna  to  that  of 
the  radius.  It  is  limited  above  by  the  ulnar  origin  of  the  supinator  brevis  ;  below, 


Capsule  of  elbow-joint 
Cushion  of  fatty  tissue 

Membranous  tissue  joining  the 
orbicular  ligament  to  the  neck 
of  the  radius 

RADIUS 

Orbicular  ligament 


Capsule  of  elbow 


FIG.  301. — ORBICULAR  LIGAMENT. 
(The  head  of  the  radius  removed  to  show  the  membranous  connection  of  this  ligament  with  the  radius.) 


Orbicular  ligament 


External  lateral 
ligament 


Posterior  ligament 


FIG.  302. — EXTERNAL  VIEW  OK  THE  ELBOW-JOINT. 


by  the  ulnar  sigmoid  of  the  radius.  It  is  a  modified  form  of  radio-ulnar  perios- 
teum. It  is  an  intermuscular  septum  between  the  flexor  and  extensor  muscles 
on  the  forearm.  It  has  a  posterior  and  an  anterior  surface,  a  radial  and  an  ulnar 
attached  border.  On  its  anterior  surface  you  will  find  the  origin  of  a  part  of  the 
flexor  profundus  digitorum,  and  the  flexor  longus  pollicis  and  pronator  quadratus 
muscles.  Between  these  you  will  see  the  anterior  interosseous  nerve  and  vessels. 


434 


PRA  CTICAL    ANA  TOMY. 


On  the  posterior  surface  are  the  three  extensors  of  the  thumb,  and  the  posterior 
interosseous  nerve  and  vessels.  An  upper  st?ong  band  of  this  membrane  is  called 
the  oblique  ligament.  (Fig.  303.) 


Upper  edge 
of  inter- 
osseous 
membrane 


FIG.  303. — INTERNAL  VIEW  OK 


Anterior  radio-ulnar 
ligament 

Internal  lateral  liga- 
ment of  wrist 
Flexor  carpi  uluaris 


External  lateral  ligament 

of  wrist 
Anterior  radio-carpal 

ligament 

Tendon  of  flexor  carpi 
radialis 


Capsular  ligament  of  first 
oarpo-metacarpal  joint 


FIG.  304. — ANTERIOR  VIEW  OF  \\  KISI. 


THE  INFERIOR   RADIO-ULNAR  ARTICULATION. 

1.  Class. — Diarthrosis,  because  of  free  motion  and  a  capsule. 

2.  Subdivision. — Ginglymus,  because  of  motion  in  two  directions  only. 

3.  Technical  Name. — Inferior  radio-ulnar  articulation  ;  common,  none. 

4.  Ostcologieal  I 'nits. — Radius  and  ulna. 

5.  Snl>tJrt'isioii(i/  /W/'/.v. — Head  of  ulna,  sigmoid  of  radius.      (Fig.  246.) 


ARTICULA  TIONS.— LIGAMENTS. 


435 


6.  Articular  Surfaces. — Ulnar  of  radius,  radial  surface  of  ulna. 

7.  Basis. — A  modified  capsule,  lined  by  synovial  membrane. 

8.  Local  Parts  of  Capsule. — An  anterior  radio-ulnar,  posterior  radio-ulnar, 
triangular  fibro-cartilage. 

9.  Strengthening  Bands. — None  ;  periosteal  purely. 

10.  Incorporated  Tendons  of  Obsolete  Muscles. — None. 

1 1.  Blood-supply. — Anterior  interosseous  and  anterior  carpal.      (Fig.  247.) 

1 2.  Nerve-supply. — Anterior  and  posterior  interosseous. 

13.  Ligamentous  Muscles. — Pronator  quadratus  and  supinator  longus. 
Locate  and  give  the  attachments  of  the  anterior  radio-ulnar  ligament. 

It  is  attached  to  the  radio-ulnar  triangular  fibro-cartilage  and  styloid  process. 
It  is  located  on  the  anterior  part  of  the  bones. 

Locate  and  give  the  attachments  of  the  posterior  radio-ulnar  ligament. 

It  is  attached  to  the  radius,  ulna,  and  triangular  fibro-cartilage  anteriorly 
and  posteriorly. 


Posterior  radio-carpal 
ligament 


Capsule  of  carpo-meta- 
carpal  joint  of  thumb 


Posterior  radio- 
ulnar  ligament 


Internal  lateral 
ligament  of  wrist 


FIG.  305. — POSTERIOR  VIEW  OF  WRIST. 


THE   RADIO-CARPAL  ARTICULATION. 

1.  Class. — Diarthrosis,  because  of  free  motion  and  a  capsule. 

2.  Subdivision. — Condylarthrosis,   because    rotation   on   a   vertical    axis    is 
wanting  ;  /.  t\,  there  is  no  axial  rotation. 

3.  Teclinical  Name. — Radio-carpal  articulation. 

4.  Osteological  Units. — Radius,  scaphoid,  semilunar,  cuneiform,  cartilage. 

5.  Subdivisional  Parts  of  Units. — None. 

6.  Articular  Surfaces. — According  to  the  general  rule. 

7.  Basis. — A  modified  and  highly  specialized  capsule. 

8.  Local  Parts  of  Capsule. — Anterior,  posterior,  internal,  external. 

9.  Strengthening  Bands. — None  ;  purely  periosteal. 

10.  Incorporated  Tendons  of  Obsolete  Muscles. — None. 

11.  Bony  Limitations. — Radial  and  ulnar  styloids. 

1 2.  Blood-supply. — Anterior  and  posterior  carpal  arterial  arches. 

13.  Ligamentous  Muscles. — (i)The  flexors  of  the  carpus,  on  radius  and  ulna  ; 
(2)  the  extensors   of  the  carpus,  on  radius  and  ulna  ;   (3)  the  sublime  and  pro- 


436 


PRACTICAL  ANATOMY. 


found  digital  flexors  ;  (4)  the  flexor  longus  pollicis  ;  (5)  the  extensor  communis 
digitorum  ;  (6)  the  special  extensor  of  the  little  finger ;  (7)  the  special  extensor 
of  the  index  finger;  (8)  the  three  extensors  of  the  thumb.  Total,  14. 

Explain  fully  tJie  most  important  ligament  in  the  radio-carpal  articulation. 

The  most  important  is  the  triangular  fibro-cartilage.  It  may  be  described  as 
having  :  (i)  A  base,  attached  to  the  margin  of  the  radius  ;  (2)  an  apex,  attached 
to  the  fossa  at  base  of  ulnar  styloid  ;  (3)  an  anterior  border,  attached  to  radio- 


Synovial  sac  of  the  inferior  radio- 
uluar  joint 


Synovial  sac  of  the  carpus 


Synovial  sac,  occasionally  separate, 
for  the  fourth  and  fifth  metacar- 
pal  bones 


Synovial  sac  of  the  wrist-joint 


Synovial  sac  of  the  carpo- 
metacarpal  joint  of  the 
thumb 


Lateral  ligaments  of  the  metacarpo- 
phalangeal.  and  inter-phalangeal 
joints 


!•'!(;.   306.— SYNOYIAI.  MKMBRANKS  OK  \\KIM,   HAM>.    \M>  I-INC.KKS. 

carpal  and  radio-ulnar  ligaments  ;  (4)  a  posterior  border,  attached  to  the  radio- 
carpal  and  radio-ulnar  ligaments;  (5)  an  upper  or  ulnar  articular  surface  (con- 
cave) ;  (6)  a  lower  or  cuneiform  surface  (concave). 

1  !<>:,<  does  tltis  cartilage  differ  from  all  otlier  Jihro-eartiln^es. 

It   niters   into  the   formation  of  two   distinct   articulations,  the   inferior  radio- 
ulnar  and  radio -Carpal,  separating  them  completely. 

/I'////  lioio  ninny  hones  does  the  end  of  tlie  radius  articulate  f 
With  the  scaphoid  and  scmilunar. 


ARTICULA  TIONS.  —LIGAMENTS.  43  7 

Give  tlic  attachments  of  the  internal  lateral  ligament  of  the  radio-carpal  articu- 
lation. 

Its  apex  is  attached  to  the  styloid  process  of  the  ulna ;  its  base  to  the  pisi- 
form and  cuneiform  bones,  and  to  the  anterior  annular  ligament. 

Give  attachments  of  the  external  lateral  ligament  of  the  radio-carpal  articulation. 

Its  apex  is  attached  to  the  apex  of  the  radial  styloid  process  ;  its  base  to  the 
scaphoid  and  trapezium. 

Give  the  attachments  of  the  anterior  radio-carpal  ligament. 

It  is  attached  above  to  the  radius  and  anterior  radio-ulnar  ligament ;  below, 
to  the  two  rows  of  carpal  bones. 

Give  the  attachments  of  the  posterior  radio-carpal  ligament. 

It  is  attached  above  to  radius,  styloid,  and  fibre-cartilage  ;  below,  to  the  first 
row  of  carpal  bones. 

Does  the  synovial  cavity  of  the  radio-carpal  articulation  communicate  with  the  in- 
ferior radio-ulnar  or  carpal  articulations  ? 

No. 

CARPAL  ARTICULATIONS. 

How  may  we  consider  the  carpal  articulations  ? 

(i)  The  joints  of  the  first  row — consisting  of  four  short  bones  ;  (2)  the  joints 
of  the  second  row — consisting  of  four  short  bones;  (3)  the  junction  of  the  two 
rows — called  the  medio-carpal  joint. 

Name  the  short  bones  in  the  first  and  second  rows. 

The  scaphoid,  semilunar,  cuneiform,  and  pisiform  ;  trapezium,  trapezoid,  os 
magnum,  and  unciform. 

Name  the  ligaments  of  the  first  row. 

They  are  all  connected  by  two  dorsal  and  two  palmar  and  two  interosseous 
ligaments  to  each  other,  except  the  pisiform. 

How  may  the  pisiform  bone  be  regarded  ? 

It  may  be  regarded  as  a  sesamoid  bone  developed  in  the  tendon  of  the  flexor 
carpi  ulnaris,  and  connected  by  a  capsule  to  the  cuneiform  bone. 

How  are  the  bones  of  the  second  row  united  ? 

By  three  dorsal,  three  palmar,  and  two  interosseous  ligaments.  The  articu- 
lations of  the  first  and  second  rows  belong  to  the  diarthrodial  class  and  arthrodial 
subdivision  of  joints. 

Name  the  ligaments  of  the  medio-carpal  articulation. 

These  are  the  anterior,  posterior,  medio-carpal,  and  transverse  dorsal  ligaments. 
To  dissect  this  region  cut  through  dorsal  ligaments. 

Give  the  attachments  of  the  anterior  annular  ligament. 

Internally  it  is  attached  to  the  unciform  process  of  the  unciform  bone,  and  the 
pisiform  bone  ;  externally,  to  the  scaphoid  and  trapezium. 

How  many  insertions  has  the  flexor  carpi  ulnaris  ? 

Three  :  (i)  Into  the  pisiform  bone  ;  (2)  into  the  unciform  process  of  the  unci- 
form bone  ;  (3)  into  the  base  of  the  fifth  metacarpal. 

Trace  the  tendon  of  the  flexor  carpi  radialis  to  its  insertion. 

It  passes  through  a  groove  in  the  os  trapezium,  and  is  inserted  into  the  base 
of  the  second  metacarpal,  sometimes  also  into  the  third  as  well. 

How  are  the  carpo-metacarpal  articulations  classified  ? 

(i)  Into  an  outer,  corresponding  to  the  thumb  ;  (2)  four  inner,  corresponding 
to  the  remaining  four  digits. 

Wliv  are  they  so  classified .' 

Because  they  belong  to  different  subdivisions  of  the  class  diarthrosis.  The 
carpo-metacarpal  of  the  thumb  is  a  saddle-shaped  arthrodia  ;  the  others  are  simply 
arthrodia. 


438 


PRACTICAL   ANATOMY. 


Name  tJic  ligaments  of  the  carpo-metacarpal  articulation  of  tlie  tJiumb.  This  is 
a  capsular  ligament. 

In  this  joint  are  found  all  the  movements  except  axial  rotation. 

Name  the  ligaments  of  the  four  inner  carpo-metacarpal  articulations. 

They  are  dorsal,  palmar,  and  interosseous. 

How  are  these  joints  supplied  witJi  nerves  / 

By  the  ulnar  median  and  posterior  interosseous. 

How  many  intcrmetacarpal  articulations  are  t lie  re  f 

Four  ;  bound  together  by  dorsal,  palmar,  and  interosseous  ligaments. 

How  are  the  heads  of  the  metacarpal  bones  held  together  ? 

By  transverse  ligaments.  In  front  of  these  ligaments  pass  the  lumbrical 
muscles,  with  the  digital  vessels  and  nerves  ;  behind,  pass  the  interossei  muscles. 


Here  are  seen  the  reflected 
tendon  of  the  rectus  and 
the  triangular  '  ilio-tro- 
ohanterio'  band 


Ischio-femoral  band 
This  is  placed  ou  the  weak 
portion  of  the  capsule 


FIG.  307. — POSTERIOR  VIEW  OK  THE  CAPSULE  OK  THE  HII--JOINT. 

The  metacarpo-pJialangeal  articulations  are  jive  in  number. 

Class,  diarthrosis  ;  subdivision,  condylarthrosis.  The  ligaments  are  lateral  and 
glenoid.  The  nerves  and  arteries  come  from  the  digital  branches. 

Classify  the  intcrplialangcal  articulations. 

They  belong  to  the  class  diarthrosis  ;  subdivision,  ginglymus.  The  proper 
ligaments  are  lateral  and  glenoid.  Dorsally,  the  tendon  of  the  extensor  com- 
munis  digitorum  acts  ligamentously  ;  on  the  palmar  surface,  the  tendons  of  the 
flexors.  The  articular  arteries  and  nerves  come,  according  to  the  rule,  from  the 
vessels  and  nerves  that  supply  the  muscles  that  move  these  joints. 

THE  HIP-JOINT. 

1.  Class. — Diarthrosis  ;  axial  rotation  and  four  angular  movements. 

2.  Subdivision. — Knarthrosis  or  ball-and-socket. 


ARTICULA  TIONS.— LIGAMENTS. 


439 


3.  Technical  Name. — Femoro-acetabular. 

4.  Osteological  Units. — Femur  and  os  innominatum. 

5.  Subdivisional  Parts. — Ilium,  ischium,  pubes,  and  femoral  head. 

6.  Articular  Surfaces. — Named  according  to  the  rule. 

7.  Basis. — A  capsule  lined  by  synovial  membrane. 

8.  Local  Subdivisions. — Ilio-femoral,  ischio-femoral,  pectineo-femoral. 

9.  Strengthening'  Bands. — Tendino-trochanteric  band. 

10.  Incorporated  Tendon  of  the  Pectineus  Muscle  (ligamentum  teres). 

1 1.  Bony  Limitations. — The  brim  and  circumference  of  acetabulum. 

12.  Nerve-supply. — Anterior  crural,  obturator,  great  sciatic,  sacral  plexus. 

13.  Blood-supply. — Obturator,  circumflex,  gluteal  and  sciatic  arteries. 

14.  Ligamentous  Muscles. — (i)  Sartorius  ;  (2)  rectus  femoris  ;  (3)  ilio-psoas  ; 


Tendon  of  rectus  pulled  up 


Tendino-trochanteric  band  passing 
between  rectus  and  vastus  externus 

Placed  on  the  weak  spot  of  capsule, 
which  is  sometimes  perforated  to 
allow  the  bursa  under  psoas  to  com- 
municate •with  joint 

Ilio-femoral  band 

Pectineo-femoral  band 


FIG.  308. — ANTERIOR  VIEW  OK  THE  CAPSULE  OK  THE  HIP-JOINT. 


(4)  pectineus  ;  (5)  gracilis  ;  (6)  adductors  longus,  brevis,  and  magnus  ;  (7)  the 
glutei  maximus,  medius,  and  minimus  ;  (8)  the  obturators  internus  and  ex- 
ternus;  (9)  the  gemelli,  superior  and  inferior;  (10)  the  tensor  vaginae  femoris  ; 
(i  i)'the  semitendinosus,  biceps,  and  semimembranosus. 

Name  the  ligaments  of  the  hip. 

(i)  The  capsular  ligament,  the  basis  of  the  joint ;  (2)  the  transverse  ligament ; 
(3)  the  ligamentum  teres,  an  interarticular  structure  ;  (4)  the  cotyloid,  a  circum- 
ferential cartilage. 

What  can  you  say  of  the  capsular  ligament  / 

It  is  one  of  the  strongest  ligaments  in  the  body.  It  is  attached  to  the  an- 
terior intertrochanteric  line  in  front ;  posteriorly,  it  is  attached  to  the  back  of  the 
neck,  one-half  of  an  inch  above  the  posterior  intertrochanteric  line. 


440  PRACTICAL  ANATOMY. 

What  can  yon  say  of  the  ilio-femoml  band  / 

This  is  the  strongest  band.  Its  apex  is  attached  below  the  anterior  inferior 
iliac  spine  ;  its  base  is  attached  to  the  anterior  intertrochanteric  line. 

Describe  t/ic  ligamentum  teres. 

Externally,  it  is  attached  to  the  lips  of  the  cotyloid  notch  ;  between  these 
extremes,  fibres  spring  from  the  transverse  ligament.  Internally,  the  ligament  is 
attached  to  the  depression  in  the  head  of  the  femur  called  the  tereal. 

Name  all  the  bony  parts  about  the  hip-joint.     (Fig.  226.) 

The  greater  and  lesser  trochanters,  the  neck  of  the  femur,  the  anterior  and 
posterior  intertrochanteric  lines,  the  anterior  inferior  spinous  process  of  the  ilium, 
the  ilio-pubal  eminence  and  line,  the  tuber  of  the  ischium,  the  ischio-pubic  ramus. 

THE  KNEE-JOINT. 

1.  Class. — Diarthrosis,  because  of  free  movement  and  constant  synovia. 

2.  Subdivision. — Ginglyinus,  because  of  motion  in  two  directions. 

3.  Technical  Name. — Tibio-femoral  articulation. 

4.  Osteological  Units. — Femur,  tibia,  and  patella. 

5.  Subdivisional  Parts. — Femoral  condyles,  tibial  tuberosities. 

6.  Articular  Surfaces. — Named  according  to  general  rule. 

7.  Basis. — A  capsule  lined  by  synovial  membrane. 

8.  Local  Subdivisions. — Internal,  external,  anterior,  posterior. 

9.  Strengthening  Bands. — Biceps,  sartorius,  semimembranosus. 

10.  Incorporated  Tendons. — Peroneus  longus,  adductor  magnus. 

1 1.  Bony  Limitations. — Patella,  tibia,  and  femur. 

12.  Nerve-supply. — Great  sciatic,  anterior  crural,  obturator. 

13.  Blood-supply. — Articular  arteries  from  the  internal  and  external  articular 
branches  of  the   popliteal  artery,  both  above  and  below  the  joint ;    from  the 
azygos  ;  from  the  recurrent  branches  of  both  the  anterior  and  posterior  tibial 
arteries  ;  from  the  anastomotica  femoris. 

14.  Ligamentous  Muscles. — (i)  Extensor  quadriceps  femoris  ;  (2)  gracilis  and 
sartorius ;  (3)  semitendinosus  and  semimembranosus  and  biceps  ;    (4)  gastroc- 
nemius  and  plantaris. 

Name  all  tJic  ligaments  of  the  knee-joint. 

(i)  The  fibrous  expansion  of  the  extensors  (strengthening  bands) ;  (2)  cap- 
sular  or  anterior  ligament  ;  (3)  posterior  ligament  or  ligament  of  Wins- 
low  ;  (4)  external  lateral  ligament ;  (5)  internal  lateral  ligament ;  (6)  ligamentum 
patellae  ;  (7)  anterior  crucial  ligament ;  (8)  posterior  crucial  ligament ;  (9) 
internal  semilunar  fibro-cartilages  ;  (10)  external  semilunar  fibro-cartila^es  ; 
(i  i)  the  coronaiy  ligament ;  (12)  the  transverse  ligament. 

/ 1  'liat  is  the  ligamcntnni  patella'  / 

It  is  a  strong  tendon  by  which  the  extensors  of  the  leg  are  inserted  into  the 
tubercle  of  the  tibia.  Its  borders  form  a  guide  to  the  surgeon  in  injecting  and 
aspirating  the  cavity  of  the  synovial  membrane  at  the  knee.  Behind  the  ten- 
don, between  this  and  the  true  capsule,  is  a  mass  of  fat  and  a  small  bursa,  re  st- 
ing on  the  bursal  segment  of  the  tubercle  of  the  tibia.  In  front  of  the  liga- 
mentum patella-  is  a  large  prepatellar  bursa,  whose  enlargement  is  known  as 
"housemaid's  knee."  Laterally,  the  ligamentum  patella-  is  continuous  with  the 
fibrous  expansion  of  the  extensor  muscles  of  the  leg. 

Describe  and  locate  tJic  ligament  of  Winslo-^<. 

It  bridges  the  space  between  the  internal  and  external  lateral  ligaments.  It 
has  perforations  for  vessels  and  nerves.  It  is  strengthened  by  an  aponeurosis 
of  the  semimembranosus  muscle.  It  forms  part  of  tin-  floor  of  the  popliteal 
space.  On  it  rest  the  popliteal  vessels. 


lagamentum  teres 


Capsular  ligament 


Capaular  ligament,  cut 
tyloid  ligament 


Capsular  ligament 


FIG.  309. — HIP-JOINT  AFTER  DIVIDING  THE  CAPSULAR  LIGAMENT  AND  DISARTICULATING 

THE  FEMUR. 


Aperture  leading  into  the 
bursa  beneath  the  quadri- 
ceps extensor 


Attachment  of  capsular,  or 
anterior  ligament  to  femur 


Fatty  tissue  within  cut  edge 
of  ligamentum  mucosum 


Anterior  crucial  ligament 


External  semilunar 
nbro-cartilage 


Coronary  ligament 


Posterior  crucial  ligament 


Internal  semilunar 
nbro-cartilage 


Transverse  ligament 
Coronary  ligament 


FIG.  310. — ANTERIOR  VIEW  OF  THE  INTERNAL  LIGAMENTS  OF  THE  KNEE-JOINT. 
29  441 


442 


PRACTICAL   ANATOMY. 


Describe  tlic  location,  length,  and  relations  of  tlic  infernal  la feral  ligament. 

It  extends  from  the  inner  condyle  to  the  tibia,  being  about  three  inches  in 
length.  Its  outer  surface  is  related  to  the  gracilis,  the  semimembranosus,  and  the 
sartorius  muscles  ;  its  deep  surface  is  in  relation  with  the  coronary  ligament  and 


Flantaris 
Outer  head  of  gastrocnemius 


External  lateral  ligament: 
anterior  portion 


Posterior  part  of  external 
lateral  ligament 
Tendon  of  popliteus 

Tendon  of  biceps 

Posterior  superior  tibio- 
nbular  ligament 


Tendon  of  adductor  magnus 


Inner  head  of 

gastrociiemius 


Tendon  of  semi-membra- 
noauB  with  its  slip  to 
thicken  the  posterior  liga- 
ment 


Internal  lateral  ligament 


Kit;.  311. — POSTERIOR  VIEW  OK  THE  KNEE-JOINT. 

Ligamentum  patellae  • 


Transverse  ligament 


Anterior  crucial 


Internal  semilunar  flbro- 
cartilage 


Posterior  crucial 
ligament 


Expansion  from  quadriceps 
extensor  tendon 


t~          External  semilunar  flbro- 
\  \  cartilage 


•Tendon  of  biceps 
External  lateral  ligament 


In..   312. — STRUCTURES  I.YIM;  ON  mi    Hi  \i>  <>!•    IHI    TMIIA.     (Right  knee.) 

semilunar   cartilage.       This    ligament    is   the    divorced   Undon  of  the   adductor 
magnus  muscle. 

/'lie  external  lateral  ligament  Consists  of  hoi,'  many  parts  / 

Of  two — an  anterior  and  a  posterior.      (I'"ig.  31  I.)      The  anterior,  the  longer. 


A  R  TICULA  TIONS.  —LIGAMENTS. 


443 


extends  from  the  tubercle  on  the  outer  femoral  condyle  to  the  head  of  the  fibula. 
Beneath  this  ligament  is  the  popliteus  tendon  in  its  synovial  sheath.  The 
posterior  portion  is  inserted  into  the  styloid.  It  binds  the  popliteus  to  the 
outer  tuberosity. 

Describe  tlie  anterior  or  capsular  ligament  proper. 

It  is  thin,  and  attached  to  the  synovial  membrane.  It  is  attached  to  the 
femur,  patella,  popliteus  muscle,  and  internal  lateral  ligament. 

Locate  and  give  function  of  the  semilunar  fibro-cartilages,  and  mention  other 
members  of  the  same  physiological  class  of  ligaments. 

They  are  two  circumferential  cartilages  resting  on  the  articular  facets  of  the 
tibia.  In  mechanics  they  correspond  to  a  ball-bearing.  They  deepen  the  cavity 
which  they  surround.  The  cotyloid  of  the  hip,  the  glenoids  of  the  shoulder 


Posterior  crucial 


lagamentum  mucosuin 


Alar  ligament 


Alar  ligament 


Synovial  pouch  under  tendon 
of  quadriceps  extensor 


FIG.  313. — ANTERIOR  VIEW  OF  THE  KNEE-JOINT,  SHOWING  THE  SYNOVIAL  LIGAMENTS. 
(Anterior  portion  of  capsule  with  the  extensor  tendon  thrown  downward.) 


and  of  the  interphalangeal  and  metacarpo-phalangeal  articulations  belong  to  the 
same  class. 

Name  the  attachments  of  the  semilunars.     (Fig.  312.) 

They  are  attached  loosely  to  the  borders  of  the  tuberosities  by  the  coronary 
ligament ;  to  each  other,  in  front,  by  the  transverse  ligament ;  their  extremities  are 
attached  to  the  depressions  in  front  and  behind  the  spine  of  the  tibia.     (Fig.  312.) 
What  can  yon  say  of  the  synovia!  membrane  of  the  knee-joint  f 
It  is  the  largest  in  the   body.      One  part  forms   a   sac  beneath   the   patella  ; 
another  extends  some  distance   above  the   attachment  of  the  capsule  above  the 
joint ;  it  covers  all  the  surface  of  the  crucial  ligaments  except  at  two  parts. 
Give  the  origin  and  insertion  of  the  crucial  ligaments.      (Fig.  312.) 
The  anterior  crucial  is  attached  to  the  tibia  in  front  of  the  spine,  and  to  the 


444  PRACTICAL  ANATOMY. 

border  of  the  inner  facet,  and  to  the  inner  and  back  part  of  the  outer  condyle. 
The  posterior  is  attached  to  the  popliteal  notch  and  adjacent  structures,  and  to 
the  outer  part  of  the  inner  condyle.  (Fig.  227.) 

Give  synonyms  for  the  crucial  ligaments. 

The  anterior  is  called  also  external  ;  the  posterior  is  called  also  internal. 

Define  ligaincnta  a/aria  and  ligamentuui  inucosum. 

The  terms  are  misnomers.  These  structures  are  parts  only  of  the  synovial 
membrane.  (See  Fig.  313.) 

NOTE. — The  student  should  endeavor  to  make  his  dissection  resemble  the 
cuts,  and  then  exercise  his  knowledge  of  osteology  by  minutely  describing  all 
the  attachments  and  relations.  Drill  of  this  kind  will  make  him  familiar  with 
the  text,  as  well  as  with  the  cadaver,  and  be  splendid  discipline  in  cultivating 
descriptive  powers — a  faculty  each  one  possesses  to  greater  or  lesser  degree. 

Name,  locate,  and  define  the  varieties  of  synovial  membrane. 

1.  The  articular,  which  is  found  in  all  freely  movable  joints,  as  the  knee 
and  hip.      In  the  foetus  it  is  said  this  membrane  covers  the  articular  surfaces  of 
the  cartilage,  as  well  as  the  interior  of  the  capsule. 

2.  The  bursal  varieties  are  of  two  kinds.      Mucous  bursae  are  found  between 
the  skin  and  bone,  as  the  prepatellar.     Synovial  bursae  are  found  between  tendons 
and  bone,  as  about  the  knee  between  the  ligamentum  patellae. 

3.  The    vaginal  kind.     This    variety  will  be  found  surrounding  the  flexor 
tendons  of  the  digits,  in  the  hand  and  foot ;  surrounding  the  long  tendon  of  the 
biceps  in  the  bicipital  canal  of  the  humerus  under  the  transverse  ligament  of  this 
bone. 

THE  TIBIO-FIBULAR  UNION. 

1.  The  superior  tibio-fibular  articulation  has  a  capsule,  an  anterior  and  a 
posterior  tibio-fibular  ligament. 

It  belongs  to  the  class  diarthrosis,  because  of  its  constant  capsule  and  syno- 
via, and  to  the  subdivision  arthrodia,  because  of  its  gliding  movement. 

The  synovial  cavity  of  this  joint  may  communicate  with  the  knee. 

The  blood-supply  comes  from  the  external  articular  and  recurrent  tibial. 

The  nerve-supply  is  from  the  recurrent  branch  of  the  external  popliteal  and 
the  inferior  external  articular. 

2.  The  tibio-fibular  interosseous  membrane  is  incomplete  above  for  about 
an  inch.     The  anterior  tibial  artery  passes  through  here,  between  the  two  heads 
of  the  tibialis  posticus  muscle,  to  the  anterior  part  of  the  leg.     The  function  of 
membrane  is  principally  for  muscular  origin.     It  has  two  borders — the  tibial  and 
the   fibular  ;  two  surfaces — the  anterior  and  the  posterior.     The  anterior  is  in 
relation   with  the  anterior  tibial  nerve  and  vessels   and  with  the  muscles  of  the 
anterior  region  of  the  leg.     The  posterior  surface  is  in  relation  with  the  tibialis 
posticus  and  the  flexor  longus  hallucis. 

3.  The  inferior  tibio-fibular  articulation.     (Fig.  317.) 
Class. — Diarthrosis,  because  of  free  movement  and  synovia. 
Subdivision. — Arthrodia,  because  of  a  gliding  movement. 

The  ligtiincnts  arc  anterior,  posterior,  transverse,  and  inferior  interosseous,  all 
of  which  are  easily  found.  The  synovial  membrane  is  continuous  with  that  of 
the  ankle-joint.  The  nerve-supply  is  from  the  internal  or  long  saphenous,  ante- 
rior and  posterior  tibial.  The  blood-supply  is  from  the  peroneal  and  its  ante- 
rior branch. 

THE  ANKLE-JOINT. 

1.  (.'/(iss. — Diarthrosis,  because  of  a  capsule  and  free  movement. 

2.  Subdivision. — (linglymus,  because  of  movement  in  two  directions. 


.  /  A'  T1CULA  TIONS.  —LIGAMENTS.  445 

3.  Technical  Name. — Tibio-fibulo-astragaloid  articulation. 

4.  Osteological  Units. — Tibia,  fibula,  and  astragalus. 

5.  Snbdivisional  Parts. — Inner  and  outer  malleoli,  astragalus. 

6.  Articular  Surfaces. — Named  according  to  the  general  rule. 

7.  Basis. — A  capsule  lined  by  a  secreting  synovial  membrane. 

8.  Local  Subdivisions. — Anterior,  posterior,  internal,  external. 

9.  Strengthening  Bands. — None. 

10.  Incorporated  Tendons  of  Obsolete  Muscles. — None. 

1 1.  Bony  Limitations. — Malleoli  of  tibia  and  fibula,  and  the  os  calcis. 

1 2.  Nerve-supply. — Anterior  and  posterior  tibial,  and  internal  saphenous. 

13.  Blood-supply. — Anterior  and  posterior  tibial  and  peroneal  arteries. 

14.  Ligamentous  Muscles. — Tibialis  anticus,  extensor  proprius  hallucis,  ex- 
tensor communis  digitorum,  peroneus  tertius,  peroneus  longus,  peroneus  brevis, 
tibialis  posticus,  flexor  longus  digitorum,  flexor  longus  hallucis,  and  the  three 
muscles  inserted  by  the  tendo  Achillis. 

Give  the  attachments  of  the  anterior  ligament  of  the  ankle-joint.     (Fig.  317.) 

It  is  attached  above  to  the  malleoli  of  the  tibia  and  fibula,  to  the  tibia,  and 
to  the  anterior  inferior  tibio-fibular  ligament ;  below,  it  is  attached  to  the  neck  of 
the  astragalus. 

Give  the  relations  of  the  anterior  ligament  of  the  ankle-joint. 

Anteriorly,  it  is  in  relation  with  the  anterior  tibial  nerve  and  vessels,  and  all 
the  muscles  of  the  front  of  the  leg  ;  posteriorly,  with  the  synovial  membrane 
and  a  fatty  mass  of  connective  tissue. 

Give  the  attachments  of  the  posterior  ligament  of  the  ankle-joint.     (Fig.  317.) 

It  is  attached  above  to  the  external  malleolus,  the  tibia,  and  the  posterior  in- 
ferior tibio-fibular  ligament ;  below,  to  the  posterior  surface  of  the  astragalus. 

Describe  the  internal  lateral  ligament.      (Fig.  318.) 

It  is  called  the  deltoid  ligament.  It  is  attached  above  to  the  lower  border 
of  the  internal  malleolus  ;  below,  to  the  astragalus,  the  sustentaculum  tali,  and 
the  calcaneo-astragaloid  ligament.  Externally,  this  ligament  is  in  relation  with 
the  tibialis  posticus  and  flexor  longus  digitorum  muscles ;  internally,  with 
the  synovial  membrane. 

Describe  the  external  ligament  of  the  ankle-joint.     (Fig.  317.) 

It  has  three  fasciculi,  or  bundles,  two  of  which  are  horizontal  and  one  ver- 
tical. The  anterior  bundle  extends  from  the  fibular  malleolus  to  the  astragalus 
in  front ;  the  posterior  bundle  from  the  malleolus  to  the  posterior  surface  of 
the  astragalus  ;  the  middle  bundle  from  the  malleolus  to  the  outer  surface  of 
the  os  calcis. 

Give  the  relations  of  the  external  ligament  of  the  ankle-joint. 

Externally,  with  the  tendons  of  the  peroneus  longus  and  peroneus  brevis 
muscles  ;  internally,  with  the  synovial  membrane. 

Describe  the  movements  in  tJic  ankle-joint. 

This  joint  is  a  hinge  ;  hence  it  has  movement  in  two  directions,  as  in  ordinary 
walking.  If,  however,  you  extend  the  foot  fully,  you  will  find  considerable 
lateral  motion.  Flex  the  foot  to  the  fullest  extent,  and  no  lateral  motion  is  pos- 
sible. Study  the  diameters  of  the  articular  part  of  the  astragalus,  and  also  the 
diameters  of  the  intermalleolar  slot,  in  which  the  astragalus  works,  and  you  will 
see  reason  for  free  lateral  mobility  of  the  foot  in  extreme  extension,  in  the  differ- 
ence in  these  diameters. 

What  can  you  say  of  the  synovial  membrane  of  the  ankle-joint .' 

It  lines  the  ligaments,  and  is  said  by  Morris  to  secrete  more  synovia  than 
any  other  synovial  membrane. 


446 


PRACTICAL  ANATOMY. 


THE  TARSUS — TARSAL  ARTICULATIONS. 

Define  tlic  i^ord  tarsus,  and  name  its  Jwnwlogue  in  the  upper  extremity. 
The  word  means  instep  ;  its  homologue  is  the  carpus,  which   means  wrist. 


POSTERO-INFERIOR  SURFACE  OF  THE 
CALCANEUM 


Abductor  minimi  digit! 
Abductor  oasis  metatarsi  quinti 


Accesaoriua  (outer  head) 


Flexor  brevis  halluci 
Abductor  ossis  metatarsi  quinti 

Flexor  brevis  minimi  digit! 

Adductor  hallucis 
Third  plantar  iuterosseous 

Second  plantar  interosseous 
First  plantar  interosseous 

Flexor  brevis  minimi  digit! 


Abductor  brevis  minimi 
digiti 

Third  plantar 
interosseous 


Second  plantar 
interosseous 


First  plantar  interosseous 


Flexor  brevis  digitorum 
Flexor  loiiguu  digitorum 


Abductor  halluois 
Flexor  brevis  digitorum 


Accessorius  i  inner  head) 


Tibialis  posticus 


Tibialis  anticua 
Peroneus  lonRU» 


Abductor  hallucis 
Flexor  brevia  halluoit 

(inner  portion) 
Flexor  brevis  hallucis 

(outer  portion) 
Adductor  hnllnois 
Trausversus  pedis 


—   Flexor  longus  hallucii 


l-ii..    314. — Till,    I.ii  i     FOOT.      (I'lantar  surface. ) 
(Study  tlic  insertion  and  location  of  tendons  on  tliis  and  compare  your  dissection  therewith.) 

To  ?c /tut  class  do  tlic  tar  sal  hones  belong .'      To  icliat  is  their  shape  adapted  / 
They   are    classified    as    short   bones  ;    tlu-ir    function    is    to    combine  gre 
strength  with  slight  motion. 


ARTICULA  TIONS.— LIGAMENTS. 


447 


Xante  the  bones  of  the  tarsus  and  indieate  tltcir  fanciful  derivation. 

(i)  Astragalus,  the  dice  bone;    (2)  calcaneum,  the   heel   bone;  (3)  scaphoid, 


Tendo  Acliillis 


Extensor  brevis 
digitorum 


Extensor  longus 
halluoia 


Extensor  brevis 
digitorum 


Peroneus  brevis 
Peroneus  tertius 


METATARSUS 


FIRST  PHALANX 


SECOND  PHALANX 
THIRD  PHALANX 


Extensor  longus  digitorum 


Fu;.   315. — THE  LEFT  FOOT.     (Dorsal  surface.) 
(Study  origin  and  insertion  of  muscles  on  this  figure  and  compare  with  your  dissection.") 

resembling  a  boat;  (4)  cuboid,  like  a  cube;  (5)  cuneiform,  like  a  wedge.  The 
ancient  shepherds  threw  dice.  The  bones  they  used  were  from  the  sheep,  hence 
our  name,  astragalus,  or  dice  bone. 


448 


PRACTICAL   ANATOMY. 


Describe  tJie  astragalus.      (Fig.  315.) 

This  bone  has  (i)  a  head,  which  articulates  with  the  scaphoid  bone  ;  (2)  a 
neck,  by  which  the  head  is  joined  to  the  body  of  the  bone  ;  (3)  a  body,  which 
has  superior,  inferior,  internal,  external,  and  posterior  surfaces. 

Give  the  importance  of  each  surface  of  the  astragalus. 

(i)  The  superior  surface  articulates  with  the  tibia  ;  (2)  the  external  surface 
articulates  with  the  fibular  malleolus  ;  (3)  the  internal  surface  articulates  with 
the  tibial  malleolus;  (4)  the  inferior  surface  articulates  with  the  calcaneum  ;  (5) 
the  posterior  surface  has  a  groove  for  the  flexor  longus  hallucis. 

Describe  the  calcaneum  or  Jic el-bone.      (Fig.  315.) 

This  bone  has  six  surfaces — anterior,  posterior,  superior,  inferior,  internal, 
and  external. 

Give  the  importance  of  each  surface. 

(i)  The  anterior  surface  articulates  with  the  cuboid  bone  ;  (2)  the  posterior 
surface  has  the  tendo  Achillis  attached  to  it ;  (3)  the  external  surface  has  two 
peroneal  grooves  and  a  tubercle  between  them  ;  (4)  the  internal  surface  has  the 


FIG.  316. — SECTION  TO  SHOW  TMK  SYNOVIAI.  CAVITIES  OK  THK  FOOT. 


i.  Posterior  calcaneo-astragaloid. 
4.  Tarsal. 


2.  Calcaneo-cuboid. 
5.  Cubo-metatarsal. 


3.  Anterior  calcaneo-astragalo-scaplioid. 
6.  First  inetatarso-cuneiform. 


sustentaculum  tali  and  a  groove  ;  (5)  the  inferior  surface  has  the  three  important 
tubercles  ;  (6)  the  superior  surface  has  an  astragaloid  articular  surface. 

Name  and  give  importance  of  the  tubercles  of  tlie  calcaneum.      (Fig.  314.) 

(i)  The  inner  tubercle  gives  origin  to  the  abductor  hallucis,  the  flexor  brevis 
digitorum,  and  the  abductor  minimi  digiti ;  (2)  the  outer  tubercle  gives  origin 
to  the  abductor  minimi  digiti,  and  to  the  inconstant  abductor  ossis  metatarsi 
quinti ;  (3)  the  anterior  tubercle  gives  attachment  to  the  short  plantar  or  cal- 
caneo-cuboid  ligament. 

Describe  the  scaphoid  bone.    (Fig.  316.) 

This  bone  articulates  posteriorly  with  the  head  of  the  astragalus  ;  anteriorly 
with  the  three  cuneiform  bones.  The  superior,  inferior,  and  external  surfaces  art- 
rough,  for  the  attachment  of  ligaments.  The  internal  surface  has  the  tuberosity, 
into  which  is  inserted  the  tibialis  posticus  muscle. 

Describe  the  cuboid  bone.     (Fig.  316.) 

It  has  six  surfaces  :  (i)  The  anterior  articulates  with  the  bases  of  the  fourth 
and  fifth  tnrtatarsals  ;  (j)the  posterior  articulates  with  the  calcaneum;  (3)  tin- 
internal  articulates  with  the  scaphoid  (sometimes)  and  external  cuneiform  ;  (4) 
the  superior  is  rough,  for  attachment  of  ligaments  ;  (5)  the  inferior  has  a  groove 


ARTICULA  TIONS.— LIGAMENTS. 


449 


for  the  peroneus  longus  ;  (6)  the  outer  is  almost  negative,  and  is  continuous  with 
the  inferior  surface. 

Can  you  say  anything  more  about  the  inferior  surface  of  tJic  cuboid  bone  f 

Yes  ;  it  has  a  ridge  behind  the  peroneal  groove,  for  the  attachment  of  the 
long  calcaneo-cuboid  ligament ;  this  ridge  terminates  externally  in  the  sesamoid 
articular  surface,  which  articulates  with  the  peroneal  sesamoid  bone,  in  the 
tendon  of  the  peroneus  longus.  The  flexor  brevis  hallucis  also  derives  its  origin 
on  this  surface  of  the  bone.  (Fig.  314.) 

Describe  t/ie  surfaces  of  the  internal  cuneiform. 

(i)  The  internal  surface  has  the  insertion  of  the  tibialis  anticus  ;  (2)  the  exter- 
nal articulates  with  the  second  metatarsal  and  middle  cuneiform  ;  (3)  the  anterior 


Antero-inferior  tibio-flbular 
ligament 


Anterior  ligament  of  ankle-joint 


Outer  extremity  of  the 

mterosseous  ligament 


External  calcaneo- 
scaphoid  ligament 


Postero-inferior  tibio- 
flbular  ligament 


—  Fasciculus  of  posterior 
ligament  of  ankle 


Posterior  fasciculus  of 
external  lateral  ligament 


ligament 
Internal  calcaneo-cuboid 


Dorsal      External    Middle  fasciculus  of  external  lateral 
alcaneo-    calcaneo-  ligament  of  the  ankle 

cuboid        astragaloid 
ligament 


FIG.  317. — EXTERNAL  VIEW  OF  THE  LIGAMENTS  OF  THE  FOOT  AND  ANKLE. 

articulates  with  the  first  metatarsal  bone  ;  (4)  the  posterior  articulates  with  the 
scaphoid  bone  ;  (5)  the  inferior  has  the  insertion  of  the  tibialis  posticus. 

Describe  the  surfaces  of  the  middle  cuneiform. 

(i)  The  anterior  articulates  with  the  second  metatarsal  bone  ;  (2)  the  posterior 
articulates  with  the  scaphoid  bone  ;  (3)  the  internal  articulates  with  the  internal 
cuneiform  bone  ;  (4)  the  external  articulates  with  the  external  cuneiform  bone  ; 
(5)  the  superior  surface  is  rough,  for  ligamentous  attachment;  (6)  into  the  in- 
ferior surface  is  inserted  the  tibialis  posticus  muscle  and  ligaments. 

Describe  the  surfaces  of  the  external  cuneiform. 

(i)  The  anterior  articulates  with  the  third  metatarsal  ;  (2)  the  posterior  with 
the  scaphoid  bone  ;  (3)  the  internal  with  the  middle  cuneiform  bone  ;  (4)  the 
external  with  the  fourth  metatarsal  and  cuboid  bone  ;  (5)  the  inferior  is  for 
tibialis  posticus  and  ligaments  ;  (6)  the  superior  is  for  ligamentous  attachment. 


Internal  lateral 
ligament 


Inferior  cal- 

ooneo-scaphoid 

ligament 


Short  plantar  ligament  Long  plantar  ligament 


FIG.  318. — INNER  VIEW  OK  THE  ANKLK  AND  THE  TARSUS,  SHOWING  THE  GROOVE  FOR  THE 
TENDON  OF  THE  TIBIAI.IS  POSTICUS. 


Long  plantar  or  long  Inferior 
calcaneo-cuboid  ligament 


Tendon  of  peroneus  longus 


GROOVE  FOR  FLEXOR  LONGUS 
HALLUCIS 

Inferior  caloaneo-acaphoid 

ligament 

Short  plantar  or  short  interior 
calcaneo-cuboid  ligament 


TUBERCLE  OF  SCAPHOID 


INTERNAL  CUNEIFORM 


Insertion  of  peroueus 
longus 


1'IC.     319.—  Lll.AMIM^    01       IHI      Soil     (,|      Tin.;    I.KI   I 
450 


AR T1CULA  TWNS.  —L IGAMENTS.  45 1 

Give  comparative  size  of  the  cuneiform  bones. 

The  internal  cuneiform  is  the  largest  bone  ;  the  middle  cuneiform  is  the 
smallest  bone  ;  the  external  cuneiform  is  intermediate  in  size. 

Name  the  principal  muscular-traction  points  in  and  about  the  tarsus,  and  indi- 
cate the  muscle  attached  thereto. 

(i)  Calcaneum  for  the  tendo  Achillis  ;  (2)  calcaneum  for  the  abductor  hallucis 
and  flexor  brevis  digitorum  ;  (3)  calcaneum  for  the  abductor  minimi  digiti  and 
accessorius  ;  (4)  calcaneum  for  the  extensor  brevis  digitorum  ;  (5)  sustentaculum 
tali  groove  for  the  tendon  of  flexor  longus  hallucis  ;  (6)  the  tuberosity  of  the 
scaphoid  bone  for  the  tibialis  posticus  ;  (7)  the  internal  cuneiform  for  the  tibialis 
anticus  ;  (8)  the  first  metacarpal  for  the  peroneus  tertius  and  tibialis  anticus  ; 
(9)  the  fifth  metatarsal  for  the  peroneus  brevis  ;  (10)  cuboidal  groove  for  the  ten- 
don of  peroneus  longus. 

Locate  the  medio-tarsal  articulation  by  limitation,  and  name  its  ligaments. 

This  joint  is  limited  posteriorly  by  the  calcaneum  and  astragalus  ;  anteriorly, 
by  the  scaphoid  and  cuboid.  (Fig.  316.)  The  ligaments  are  :  (i)  The  external 
calcaneo-scaphoid  ;  (2)  the  inferior  calcaneo-scaphoid  ;  (3)  the  astragalo-scaphoid 
ligament ;  (4)  the  internal  or  interosseous  calcaneo-cuboid  ligament ;  (5)  the  long 
inferior  calcaneo-cuboid  ligament;  (6)  the  short  inferior  calcaneo-cuboid  liga- 
ment ;  (7)  the  dorsal  calcaneo-cuboid  ligament. 

Give  the  attachments  of  the  long  inferior  calcaneo-cuboid  ligament  and  the 
common  name  for  the  same.  (Fig.  319.) 

It  is  also  called  the  long  plantar  ligament.  It  is  attached  to  the  whole  infe- 
rior surface  of  the  calcaneum  behind ;  to  the  cuboid  and  bases  of  the  meta- 
tarsals  in  front. 

Can  yon  mention  any  other  important  fact  in  regard  to  the  long  plantar 
ligament  / 

Yes  ;  it  completes  the  canal  for  the  peroneus  longus  muscle,  and  also  gives 
origin  to  the  adductor  hallucis  and  the  flexor  brevis  minimi  digiti.  (Fig.  319.) 

Give  the  attachments  of  the  short  inferior  calcaneo-cuboid  ligament  and  its 
common  name. 

It  is  called  the  short  plantar  ligament.  It  is  attached  to  the  under  surfaces 
of  the  calcaneum  and  cuboid.  (Fig.  319.) 

From  what  source  does  the  medio-tarsal  joint  receive  its  nerve-supply  ? 

From  the  outer  division  of  the  anterior  tibial,  the  musculo-cutaneous,  and 
the  external  plantar  nerves. 

From  ivhat  source  does  the  medio-tarsal  joint  receive  its  blood-supply  ? 

From  the  anterior  tibial,  the  dorsalis  pedis,  and  the  internal  and  external 
plantar  arteries. 

What  class  and  subdivision  does  the  medio-tarsal  articidation  belong  in  ? 

(i)  The  astragalo-scaphoid  joint  is  diarthrosis  by  class,  and  enarthrodia  by 
subdivision  ;  (2)  the  calcaneo-cuboid  is  diarthrosis  by  class,  and  saddle  arthrodia 
by  subdivision. 

Name  the  ligaments  of  the  calcanco-astragaloid  articulation. 

(i)  The  external  calcaneo-astragaloid  ligament;  (2)  the  internal  calcaneo- 
astragaloid  ligament ;  (3)  the  posterior  calcaneo-astragaloid  ligament ;  (4)  the 
interosseous  calcaneo-astragaloid  ligament. 

Locate  the  interosseous  ligament. 

It  extends  from  the  calcaneum  to  the  astragalus,  connecting  the  parallel 
oblique  grooves  of  these  two  bones. 

Describe  the  scapho-cuneiform  articulation. 

Class. — Diarthrosis,  because  of  free  movement  and  a  capsule. 

Subdivision. — Arthrodia,  because  of  a  gliding  movement. 

Ligaments. — Dorsal,  plantar,  and  internal. 


452 


PRACTICAL  ANATOMY. 


Describe  the  intercuneiform  articulations. 

Class. — Diarthrosis,  because  of  free  movement  and  a  capsule. 

Subdivision. — Arthrodia,  because  of  a  gliding  movement. 

Ligaments. — Dorsal,  plantar,  and  interosseous. 

Blood-supply. — Metatarsal  and  plantar  arteries. 

Nerve-supply. — Anterior  tibial  and  plantar  nerves. 

Describe  the  tarsometatarsal  articulations. 

Class. — Diarthrosis,  because  of  free  movement  and  a  capsule. 

Subdivision. — Arthrodia,  because  of  a  gliding  movement. 

Ligaments. — Dorsal,  palmar,  and  interosseous. 

Nerve-supply. — Anterior  tibial  and  plantar  nerves. 


Posterior  ligament  of  ankle- 
joint 


Posterior  part  of  the  internal 
lateral  ligament 


The  lower  part  of  the  inter- 
oaseous  membrane 


Transverse  ligament  of  inferior 
tibio-nbular  joint 


Posterior  fasciculus  of  external 
lateral  ligament 


Middle  fasciculus  of  external 
lateral  ligament 


FlG.    320.  —  LUIAMENTS   SEEN    FROM    THE    BACK    OF   THE    ANKLE-JOINT. 


Describe  the  intermetatarsal  articulations. 
Class. — Diarthrosis,  because  of  free  movement  and  a  capsule. 
Subdivision. — Arthrodia,  because  of  a  gliding  movement. 
Ligaments, — Dorsal,  plantar,  and  interosseous. 

//ow  arc  the  heads  of  the  nictatarsal  bones  connected  / 
By  rather  strong,  short,  transverse  ligaments. 
Describe  the  metatarso-phalangeal  articulations. 
( '/tiss. — Diarthrosis,  because  of  free  movement  and  a  capsule. 
Subdivision. — Condylarthrosis,  because  of  no  axial  rotation. 
Ligaments. — Lateral,  dorsal,  plantar,  sesamoul. 
Liganicntons  Muscles. — Flexors  and  extensors  of  the  digits. 
Describe  the  interphalangeal  articulations. 

Class.  —  Diarthrosis.  because  of  free  movrnu-nt. 

Subdivision. — (iinglymus,  because  of  motion  in  two  directions. 


ARTICULA  TIONS.— LIGAMENTS. 

Ligaments. — Laterals,  dorsals,  and  glenoids. 

Ligamentous  Muscles. — Flexors  and  extensors  of  the  digits. 

Nerve-supply. — Internal  and  external  plantar  nerves. 


453 


FIG.  321. — RIGHT  INNOMINATE  BONE,  EXTERNAL  ASPECT. 

Superior  border,  or  crest.  2.  Anterior  superior  iliac  spine.  3.  Posterior  superior  iliac  spine.  4,4,4. 
Superior  curved  line.  5,5-  Inferior  curved  line.  6.  Surface  between  inferior  curved  line  and 
acetabulum.  7.  Anterior  inferior  iliac  spine.  8.  Anterior  interspinous  notch.  9.  Posterior  inferior 
iliac  spine.  10.  Posterior  interspinous  notch.  II.  Spine  of  ischium.  12.  Great  sacro-sciatic  notch. 
13.  Acetabulum.  14.  Fundus  of  acetabulum.  15,15.  Circumference  of  acetabulum.  16.  Cotyloid 
notch.  17.  Spine  of  pubes.  18.  Horizontal  branch  of  pubes.  19.  Descending  branch  of  pubes. 
20,20.  Ischium.  21.  Groove  for  tendon  of  obturator  externus  muscle.  22.  Obturator  foramen. 


P.  LAC.  it  E.SAL. 

FIG.  322. — PELVIS,  ANTEKO  SUPKKIOR  VIEW,  SUPERIOR  STRAIT. 

1,1.  Internal  iliac  fossae.  2,2.  Iliac  crests.  3,3-  Anterior  superior  iliac  spines.  4,4.  Anterior  inferior 
iliac  spines.  5,5.  Ilio-pectineal  eminences.  6,6.  Horizontal  branches  of  pubes.  7.7.  Bodies  and 
symphysis  of  pubes.  8,  8.  Acetabula.  9,  9.  Tuberosities  of  iscbia.  10,  10.  Ascending  rami  of 
ischium.  II,  II.  Descending  rami  of  pubes.  12,  12.  Spines  of  ischia.  13,  13  Posterior  wall  of 
pelvic  cavity.  14,  14.  Sacro-iliac  symphyses.  15.  Sacro-vertebral  angle.  16,  16.  Superior  strait. 

THE  PELVIS — ITS  ARTICULATIONS  AND  LIGAMENTS. 

The  bones  of  the  pelvis  are  the  sacrum,  coccyx,  and  ossa  innominata.  The 
pelvis  articulates  with  the  lumbar  part  of  the  vertebral  column,  and  with  the 
head  of  the  femur.  We  m;iy  then  classify  the  articulations,  for  purposes  of  con- 
venience, as  (i)  intrinsic,  where  the  articulation  is  between  pelvic  bones  ;  (2)  ex- 
trinsic, where  the  articulation  is  between  pelvic  bones  and  bones  not  pelvic. 


PRACTICAL  ANATOMY. 

The  intrinsic  pelvic  articulations  arc  : 

(i)  The  sacro-iliac,  between  the  sacrum  and  ilium  ;  (2)  the  sacro-sciatic, 
between  the  sacrum  and  ischium  ;  (3)  the  interpubic,  between  the  pubic  bones  ; 
(4)  the  sacro-coccygeal,  between  the  sacrum  and  coccyx. 

The  extrinsic  ligaments  are  : 

(i)  The  sacro-lumbar,  between  the  sacrum  and  the  last  vertebra  of  the  lum- 
bar region  ;  (2)  the  femoro-innominate  group  of  ligaments. 

Name  tlie  ostcological  points  of  interest  in  and  about  the  pelvis. 

(i)  Symphysis  pubis,  between  the  pubic  bones;  (2)  pubic  crest,  limited  by 
the  angle  and  spine  of  pubis ;  (3)  ilio-pubic  line,  limited  by  the  spine  and  ilio- 
pubic  eminence  ;  (4)  the  ilio-pubic  eminence,  at  the  junction  of  pubis  and  ilium  ; 


FIG.  323. — FEMUR,  POSTERIOR  ASPECT. 
1,1.   Linea  aspera.      2,2.    External  division.     3.    Internal  division.     4,4.    Inferior  divisions.      5.    Iliad. 
6.    Depression   for  attachment  of  round    ligament.      7.    Neck.      8.   Great   trochanter.     9.    liigital    or 
trochameric    fossa.      IO.    Lesser  trochanter.       II.   Outer    coiulyle.      12.    Inner    condyle.      13.    Inter 
condyloid  notch.      14.   Outer  tuberosity.      15.    Inner  tuberosity. 


(5)  the  iliac  crest,  limited  by  the  superior  iliac  spines,  anterior  and  posterior;  (6) 
the  acetabulum,  at  the  junction  of  the  ilium,  ischium,  and  pubes  ;  (7)  the  fossa 
acetabuli,  the  non-articular  part  of  the  acetabulum  ;  (8)  the  cotyloid  notch,  an 
interruption  in  the  acetabular  brim;  (9)  the  lesser  sacro-sciatic  notch,  between 
the  ischial  tuber  and  spine  ;  (10)  the  ischial  spine,  between  the  greater  and  les.ser 
sciatic  notches  ;  (i  i)  the  tub'er  of  the  ischium,  one  of  the  grand  divisions  of  the 
ischium  ;  (12)  the  ischio-pubic  ramus,  between  the  pubes  and  ischium  ;  (13)  the 
obturator  foramen,  bounded  by  the  pubes  and  ischium;  (14)  the  pelvic  inlet, 
between  the  true  and  false  pelvis  ;  (15)  the  subpubic  arcade,  between  tin-  ischio- 
pubic  rami  ;  (16)  the  anterior  superior  iliac  spine,  for  the  insertion  of  Poupart's 
ligament  ;  (17)  the  anterior  inferior  iliac  spine,  lor  the  oiigin  of  the  straight  head 
of  the  reetus;  (18)  the  anterior  interspinous  notch,  between  the  anterior  iliac 


ARTICULA  TIONS.  —LIGAMENTS. 


455 


spines  ;  (19)  the  posterior  iliac  spines,  superior  and  inferior  ;  (20)  the  promontory 
of  the  sacrum  ;  (21)  the  alas  of  the  sacrum,  consisting  of  transverse  and  costal 
elemental  parts  ;  (22)  the  anterior  sacral  foramina,  for  the  anterior  sacral  nerves  ; 
(23)  the  sacro-iliac  synchondrosis,  right  and  left;  (24)  the  greater  and  lesser 


Superior  pubio  ligament 


Inferior  pubic  ligament 


FIG.  324. — ANTERIOR  VIEW  OF  THE  SYMPHYSIS  Puuis  (FEMALE,  SHOWING  GREATER  WIDTH 

BETWEEN    THE    BONES). 


Inferior  pubio  ligament 

FIG.  325. — POSTERIOR  VIEW  OF  THE  SYMPHYSIS  PUBIS,  SHOWING  THE  BACKWARD  PROJECTION  OK 
THE  SYMPHYSIAI.  SUBSTANCE  AND  THE  DECUSSATION  OF  THE  FIBRES  FROM  THE  INFERIOR 
PUBIC  LIGAMENT. 

Superior  pubic  ligament 


Inferior  pubic  ligament 


FIG.  326. — ANTERIOR  VIEW  OF  THE  SYMPHYSIS  Pi  ms  (MALE)  SHOWING  DECUSSATION  OF  THK 
FIBRES  OF  THE  ANTERIOR  LIGAMENT. 

trochanters  of  the  femur  ;  (25)  the  anterior  and  posterior  intertrochanteric  lines  ; 
(26)  the  digital  or  trochanteric  fossa  ;  (27)  the  superior  and  inferior  cervical 
tubercles  of  the  femur. 


456 


PRACTICAL   ANATOMY. 


Symphysis  Pubis : 

Class. — Amphiarthrosis,  because  of  union  by  cartilage  and  slight  motion. 

Ostcological  lUements. — The  bodies  of  the  two  pubic  bones. 

Ligaments. — Anterior,  posterior,  superior,  inferior,  and  interosseous  cartilage. 

Is  there  any  difference  bcticeen  this  joint  in  tlic  tico  sexes? 

The  joint  is  shorter  and  broader  in  the  female  than  in  the  male.     (Fig.  324.) 

Is  the  nerve-supply  of  the  sympliy sis  pubis  ice//  understood  / 

No  ;  but  it  probably  is  derived   from   the  ilio-inguinal,  ilio-hypogastric,  and 

internal  pudic  nerves. 

From  ivhat  source  does  this  articulation  derive  its  blood-supply  / 

From  the  internal   pudic,  the  obturator,  deep  epigastric,  internal  circumflex, 

iliac,  and  external  pudic  arteries. 


Foramen  for  last 

lumbar  nerve 
Intervertebral  body 
between  last  lum- 
bar and  first  sacral 
vertebrae 


Foramen  for  anterior  primary  branch  of  fourth 
lumbar  nerve 


The  ilio-lumbar 
ligament 


The  sacro-lumbar 
ligament 


Superior  sacro-iliac 
ligament 


Anterior  sacro-iliac 
ligament 


Great  aacro- sciatic 
ligament 


Lesser  sacro-sciatic 
ligament 


Fiu.  327. — ANTERIOR  VIEW  OK   1111. 


Wlial  influence  has  pregnancy  on  t/ic  interosseous  cartilage  beticeen  the  pubic 
bones  ? 

The  cartilage  becomes  softer  and  the  blood-supply  more  abundant. 

Is  there  any  special  difference  in  tlic  hiterosseons  cartilage  in  /lie  male  and 
female  f 

It  is  thicker  in  the  female  than  in  the  male. 

\Vliat  is  sympliysotomy  or  sympliysiotomy  .' 

Cutting  through  the  pubic  symphysis  to  increase  tin-  conjugate  diameters  of 
the  pelvic  canal.  In  this  obstetric  operation  all  the  ligaments  of  the  symphysis 
pubis  are  cut. 

Sacro-iliac  Articulation  and  Its  Ligaments  : 

Class. — AmphiarthroMs,  bones  united  by  cartilage  and  slight   motion. 


ARTICULATIONS. —LIGAMENTS.  457 

Osteological  Units. — The  sacrum  and  ilium. 

Snbdii'isional  Parts. — Auricular  surfaces  of  the  sacrum  and  ilium. 

Nerve-supply. — Superior  gluteal,  sacral  plexus,  first  and  second  sacral  nerves. 

Blood-supply. — Gluteal,  ilio-lumbar,  and  lateral  sacral  arteries. 

Morphologically,  what  is  that  fart  of  the  sacrum  that  articulates  with  the 
auricular  part  of  the  ilium  / 

It  is  the  result  of  a  peculiar  modification  of  the  costal  elements  of  the  first 
three  sacral  vertebrae. 

Name  and  locate  the  ligaments  of  this  articulation. 

(i)  Anterior  sacro-iliac,  from  pelvic  brim  to  greater  sacro-sciatic  foramen  ; 
(2)  posterior  sacro-iliac,  from  back  of  sacrum  to  iliac  crest ;  (3)  superior  sacro- 
iliac,  from  sacral  base  to  iliac  fossa  ;  (4)  inferior  sacro-iliac,  from  sacrum  to  pos- 
terior iliac  spine  ;  (5)  interosseous  ligament  is  between  the  two  spines. 

The  function  of  the  sacro-iliac  ligaments  is  to  bind  the  sacrum  to  the  ilium. 


Falciform  process  of  the 
great  ligament 

.  Tendon  of  biceps  muscle,  continuous  with 
the  great  sacro-sciatic  ligament 

FIG.  328. — SACRO-SCIATIC  LIGAMENTS.     (Posterior  view. ) 

They  are  purely  of  periosteal  derivation.  The  plate  of  cartilage  between  the 
bones  may  become  ossified,  just  as  the  ligaments  of  the  vertebral  column  some- 
times do.  Occasionally,  a  distinct  synovial  cavity  is  found  in  the  center  of  this 
cartilage. 

Sacro-ischiatic  Ligaments  : 

Hozv  many  ligaments  unite  the  sacrum  and  ischium  ?     (Fig.  328.) 

Two  ;  the  common  name  for  these  is  sacro-sciatic,  which  is  a  contraction  of 
the  true  word  for  purposes  of  euphony.  The  common  names  are  :  (i)  Greater 
or  posterior  sacro-sciatic  ligament;  (2)  lesser  or  anterior  sacro-sciatic  ligament. 

Locate  the  greater  ligament. 

The  greater  or  posterior  sacro-sciatic  ligament  is  attached  above  to  the  mar- 
gin of  the  sacrum  and  coccyx  and  to  the  posterior  inferior  iliac  spine  ;  below  to 
the  inner  margin  of  the  tuber  of  the  ischium  and  ascending  ramus  of  the  ischium 
for  about  two  inches. 
3° 


PRACTICAL  ANATOMY. 


\\liat  is  the  special  name  for  the  tu'o  inches  of  t  lie  greater  sacro-sciatic  ligament 
that  is  prolonged  on  to  the  inner  margin  of  the  ascending  rannts  of  the  iscluum  f 

It  is  called  the  falciform  ligament.  (Fig.  328.)  This  ligament  unites  with 
the  obturator  fascia  to  strengthen  Alcock's  canal,  in  which  canal  are  located  the 
internal  pudic  nerve  and  vessels. 

What  are  the  functions  of  the  greater  sacro-sciatic  ligament,  exclusive  of  its 
special  part — the  falciform  ligament  / 

It  gives  partial  origin  to  the  gluteus  maximus  muscle,  and  converts  the  lesser 
sacro-sciatic  notch  into  a  foramen. 

Name  the  structures  that  pass  through  the  lesser  sacro-sciatic  foramen. 

(i)  The  tendon  of  the  obturator  muscle  and  its  nerve;  (2)  the  internal 
pudic  nerve  and  vessels. 

Locate  the  lesser  sacro-sciatic  ligament. 

The  lesser  or  anterior  sacro-sciatic  ligament  is  attached  above  to  the  margin 


Superior  saero-iliac 
ligament 


Anterior  eacro-iliac 

ligament 

Inferior  saoro-iliac 
ligament 


Small  sacro-sciatic 
ligament 


Great  sacro-sciatic 
ligament 


Fi<;.  329. — VERTICAL  ANTKRO-POSTKRIOK  SECTION  OK  Tin:  I'KI.VIS. 


of  the  sacrum  and  coccyx  ;  below,  to  the  spine  of  the  ischium.     This  ligament 
converts  the  greater  sacro-sciatic  notch  into  a  foramen. 

Name  structures  transmitted  hy  the  greater  sacro-sciatic  foramen. 

(l)  The  pyriformis  muscle,  above  which  pass  out  the  glutcal  nerve  ami 
vessels,  and  below  which  muscle  pass  out  the  sciatic  vessels  and  nerves,  the 
internal  pudic  nerve  and  vessels,  and  the  branch  of  the  sacral  plexus  that  sup- 
plies the  obturator  muscle. 

\arne  all  (he  structures  that  /cave  tlie  pelvis  through  the  greater  sacro-sciatic 
foramen,  cross  (he  iscl/ial  spine,  and  reenter  the  pelvis  through  the  lesser  sacro- 
sciatic  foramen. 

(l)  The  branch  of  the  sacral  plexus  to  the  obturator  interims;  (2}  the 
internal  pudic  nerve  ;  (3)  the  internal  pudic  vessels. 

\\7iat  becomes  of  these  structures  on  reentering  the  pelvis  / 


A  R  T1CULA  TIONS.  —LIGAMENTS. 


459 


They  enter  Alcock's  canal,  which  is  a  delamination  of  the  obturator  fascia 
strengthened  by  the  falciform  ligament,  a  special  part  of  the  greater  sacro-sciatic 
ligament. 

2  2 

1 


FIG.  330. — COCCYX,  ANTERIOR  ASPECT. 

I.   Base.     2,  2.   Cornua.      3.   Second  coccygeal  vertebra.      4.   Third  coccygeal  vertebra.      5.    Fourth  coc- 
cygeal  vertebra.      6.    Fifth  coccygeal  vertebra. 


Fie';.  331. — VERTEBRAL  COLUMN,  LATERAL  ASPHT. 

1-7.  Cervical  vertebrae.  8-19.  Dorsal  vertel>ne.  20-24.  Lumbar  vertebra'.  A,  A.  Spinous  processes. 
B,  B.  Articular  facets  of  transverse  processes  of  first  ten  dorsal  vertebras.  C.  Auricular  surface  of 
sacrum.  I).  Foramina  in  transverse  processes  of  cervical  vertebrae. 

The  Sacro-coccygeal  Articulation  and  Ligaments  : 

1 .  Class. — Amphiarthrosis,  bones  united  by  cartilage. 

2.  Osteological  Units. — The  sacrum  and  coccyx. 

3.  Subdivisio nal  Parts. — Sacral  and  coccygeal  cornua. 

4.  Nerve-supply. — The  fourth,  fifth  sacral,  and  coccygeal  nerves. 


460 


PRACTICAL  ANATOMY. 


5.  Blood-supply. — Middle  sacral  and  lateral  sacral  artery. 

6.  Ligaments. — Anterior  sacro-coccygeal  ligament,  on  the  front  of  bodies  ; 
posterior  sacro-coccygeal  ligament,  on   posterior  part  of  bodies  ;  supracornual 
ligament,  a  prolongation  of  the  supraspinous  ligament  ;  intertransverse  ligament, 
analogous    to  the  intertransverse  ligaments  of  the  true  vertebrae  ;    intervertebral 
substance  of  jelly-like  cartilage. 

The  Sacro- vertebral  Articulation  and  its  Ligaments  : 

1.  Class. — Amphiarthrosis  between  the  bodies  of  the  vertebrae. 

2.  Class. — Diarthrosis  between  the  articular  processes. 

3.  Subdivision. — Arthrodia,  because  of  a  gliding  movement. 

4.  Osteological  Units. — Same  as  between  two  vertebrae. 

5.  Subdivisional  Parts. — Same  as  in  juxtaposition  of  vertebras. 


Lateral  expanded  portion 


Median  longitudinal  band 


Fic..  332. — POSTERIOR  COMMON  LIGAMENT  OK  THE  SPINE.     (Thoracic  region.) 
(Pedicles  cut  through,  and  posterior  arches  of  vertebra  removed.) 

6.  Nerve-supply. — Fourth  and  fifth  lumbar  and  sympathetic. 

7.  Blood-supply. — Lateral  sacral,  last  lumbar,  ilio-lumbar. 

8.  Special  Name. — Sacro-vertebral  angle. 

9.  Ligaments   of  Sacro-vertebral  Articulation. — (i)   Prolongation  down  wan 
of  the  ligaments  of  the  vertebral  column   under  the  same  name.     They  may  be 
modified  to  some  extent  to  meet  the  particular  demands  of  a  special  region  ;  for 
this  modification   you  can  account  philosophically  :  growth  is  the  correlative  of 
function.     (2)  Sacro-lumbar  ligament,  triangular  in  shape.     (3)  Ilio-lumbar  liga- 
ment, triangular  in  shape. 

THE  VERTEBRAL  COLUMN  AND  ITS  Lu; AMEN  r>. 
Of  what  is  the  vertebral  column  composed .' 
Of  thirty-three  irregular  bones,  called  vertebra.-.     They  arc  classified  as  true 


AR  TICULA  TIONS.  —LIGAMENTS.  46 1 

and  false  vertebrae.  The  false  vertebrae,  nine  in  number,  five  sacral  and  four 
coccygeal,  make  by  their  fusion  the  sacrum  and  coccyx. 

Name  tlie  regions  of  tlie  vertebral  column  and  give  sonic  reasons  for  a  regional 
subdivision  of  tJic  column. 

The  vertebral  regions  and  the  number  of  bones  in  each  are  :  (i)  Cervical 
reg'on,  containing  seven  bones  ;  (2)  dorsal  or  thoracic  region,  containing  twelve 
boius  ;  (3)  lumbar  region,  containing  five  bones  ;  (4)  sacro-coccygeal  region,  con- 
taining nine  bones.  Subdivision  of  the  vertebral  column  into  regions  depends  on 
a  difference  in  form  of  the  bones,  while  this  difference  in  the  form  depends  on  the 
function  of  the  region  in  which  the  bones  are  located  ;  growth  predetermines 
form,  and  is  the  correlative  of  function. 

What  is  tlie  natural  arrangement  of  adjacent  vertebne  to  cadi  other  / 

They  are  in  juxtaposition — that  is,  one  next  to  another,  with  parallelism   of 


Portion  of  ligamen- 
tum  subflavum  re- 
moved to  show  the 
articular  cavity 


Iiigamentum 
subflavum 


1/11 ;-    333- — LlGAMENTA    SUBFLAVA    IN    THE    LUMBAR    REGION. 


homologous  parts.  Thus,  this  arrangement  among  the  bones  of  the  vertebral 
column  gives  a  logical  basis  for  studying  the  ligaments  of  the  column,  since  we 
find  :  Juxtaposition  of  bodies  ;  juxtaposition  of  pedicles  ;  juxtaposition  of  lam- 
inae ;  juxtaposition  of  articular  processes  ;  juxtaposition  of  spinous  processes  ; 
juxtaposition  of  transverse  processes. 

Wliat  is  t/ie  function  of  the  bodies  or  centra,  and  by  u'hat  ligaments  are  they 
held  together .' 

They  give  solidity  and  strength  to  the  column.  The  ligaments  of  the  bodies 
or  centra  are  the  anterior  common,  posterior  common,  and  intercentral  discs  of 
fibro-cartilage.  Their  union  forms  an  amphiarthrodial  articulation,  since  bone  is 
united  to  bone  by  cartilage  with  limited  motion. 

Give  the  function  and  relations  of  tlie  pedicles. 

The  pedicles  support  the  neural  arch.  Above  and  below  them  are  found 
the  intervertebral  notches,  which  are  converted  into  intervertebral  foramina  when 


462 


PRACTICAL   ANATOMY. 


the  vertebrae  are  in  juxtaposition.      (Fig.  335.)     These  intervertebral  foramina 
transmit  the  spinal  nerves  and  blood-vessels. 

Give  the  function  of  the  lainiiue,  name  tJieir  proper  ligaments,  and  tell  wherein 
these  ligaments  differ  liistologically  from  all  otliers  of  the  vertebral  column. 


CERVICAL 
VERTEBRA 


COSTAL  PROCESS 


TRANSVERSE  PROCESS 
COSTO-TRANSVERSE  FORAMEN 


NEURO-CENTRAL  SUTURE 
CERVICAL  RIB 


THORACIC 
VERTEBRA 


TRANSVERSE  PROCESS 
COSTO-TRANSVERSE  FORAMEN 


NEURO-CENTRAL SUTURE 
RIB 


TRANSVERSE  PROCESS 
LUMBAR  RIB 


NEURO-CENTRAL  SUTURE 
COSTAL  PROCESS 


I'K;.    334. —  MoKI'IlOLOCY    I'l     Till'.    TKANSVKKSK    AND    A  KTH  T  I.A  K     l'R«  X 'l-»l- >. 

The  laminae  unite  posteriorly  to  enclose  the  neural  canal.  They  are  bound 
together  by  the  interlaminar  ligaments.  These  are  composed  of  yellow  elastic 
connective  tissue,  hence  they  are  called  the  ligament. i  subllava.  The  term  sub- 
flava  means  yellowish. 


AR TICULA  776LV.V.  —LIGAMEXTS. 


463 


Give  the  function  of  the  articular  processes  and  tell  illicit  kind  of  joints  tlicv 
form  when  in  juxtaposition. 

The  articular  processes,  by  their  union,  make  the  vertebral  column  a  concrete 
whole,  the  separate  parts  of  which  column  move  or  turn  on  each  other.  They 
form  diarthrodial  articulations  of  the  arthrodial  subdivision.  The  basis  of  the 
joint  is  a  capsule  lined  by  synovial  membrane. 

Give  the  function  of  the  transverse  processes  and  explain  their  serial  morphology 
in  the  four  regions  of  the  column. 

The  transverse  processes  are  for  the  attachment  of  ligaments,  muscles,  and 
either  fully  developed  ribs,  or  rudimentary  ones,  called  costal  elements.  The 
simplest  series  is  in  the  thoracic  region.  Here  we  find  a  transverse  process  articu- 
lating with  a  rib  in  such  a  manner  as  to  leave  a  space  bounded  by  a  rib,  transverse 
process,  and  pedicle.  This  space  is  a  vascular  opening,  and  is  called  a  costo- 


The  interspinoua 
ligament 


The  supraspinoua 
ligament 


FIG.  335. — THE  INTERSPINOUS  AND  SUPRASPINOUS  LIGAMENTS  IN  THE  LUMBAR  REGION. 


transverse  space.  The  extremes  of  the  column  show  this  costo-transverse  space  : 
a  well-formed  vertebral  canal  in  the  cervical  region  ;  a  mere  collection  of  small 
foramina  in  the  lumbar  region  ;  a  depression  transmitting  a  few  small  vessels  in 
the  sacrum,  between  the  costal  and  the  transverse  element  of  the  ala  of  this  bone. 
(Fig.  334.)  In  the  cervical  region  the  rudimentary  rib  obtains  as  the  anterior 
tubercle  ;  in  the  thoracic  region  the  costal  portion  is  maximal — a  rib  ;  in  the 
lumbar  region,  the  transverse  process  is  suppressed  and  the  costal  element  is 
very  large  ;  in  the  sacral  region  the  costal  elements  of  the  first  three  sacral 
vertebrae  are  modified  to  form  the  auricular  part  of  the  sacrum,  for  articulation 
with  the  ilium. 

In  view  of  the  great  importance  of  the  subject  of  the  serial  morphology  ot 
the  vertebrae  in  your  dissections,  I  here  introduce  figure  334,  which  will  illustrate 
the  foregoing,  leaving  the  subject  of  morphology  for  the  student  to  read  up  in 
Morris. 

Give  the  function  of  the  spinons  processes  and  name  their  ligaments. 


464 


PRACTICAL  ANATOMY. 


They  are  for  the  attachment  of  muscles  and  ligaments.  Their  ligaments  are 
periosteal,  and  are  named  interspinous  and  supraspinous.  (Fig.  335.) 

What  is  the  ligaincntmn  nucluz  ? 

Literally,  the  ligament  of  the  nape  of  the  neck.  This  is  a  septum  of  con- 
nective tissue  between  the  muscles  of  the  back  of  the  neck.  Its  attachments  are 
the  external  occipital  protuberance  (Fig.  338)  and  the  spines  of  the  cervical  ver- 
tebrae. It  is  rudimentary  in  man — impossible  of  demonstration  in  practical 
anatomy,  except  as  a  very  feeble  intermuscular  connective  tissue  ;  not  being 
demonstrable  even,  in  my  experience,  as  an  intermuscular  septum,  such  as  we 
find  between  the  peronei  muscles  and  those  on  the  front  part  of  the  leg. 

Describe  the  atlas. 

This  is  the  first  of  the  cervical  series  of  vertebrae.     It  consists  of  an  anterior 


Vertical  portion  of  crucial 

ligament 
Central  odontoid  ligament 

Lateral  odontoid  ligaments 

Transverse  portion  of 
crucial  ligament 
Accessory  band  of  atlanto- 
azoidean  capsules 
Atlanto-azoidean  joint 


Oocipito-cervioal  or  cervico-basilar 
ligament 


Posterior  common  ligament 


FIG.  336. — VERTICAL  TRANSVERSE  SECTION  OF  THE  SPINAL  COLUMN  AND  THE  OCCIPITAL  I><»M 

TO  SHOW  LIGAMENTS. 

(The  cervico-basilar  (l),  though  shown  as  a  distinct  stratum,  is  really  the  deeper  part  of 
the  posterior  common  ligament  (2).) 


arch,  a  posterior  arch,  and  two  lateral  masses.  Morphologically,  its  divorced  or 
dismembered  body  obtains  as  the  odontoid  process  of  the  axis. 

Give  composition  of  the  lateral  mass. 

The  lateral  mass  consists  of  (i)  a  superior  articular  process  that  articulates 
with  the  occipital  condyle  ;  (2)  an  inferior  articular  process  that  articulates  with 
the  axis  ;  (3)  costal  process — a  rudimentary  rib  ;  (4)  a  transverse  process  for 
muscular  attachment;  (5)  a  costotransverse  foramen  for  the  vertebral  artery; 
(6)  tubercles  for  attachment  of  the  transverse  liganu nt. 

\Vhat  do   YOU  find  at  the  junction  of  the  lateral  mass  and  the  posterior  arch  / 

A  groove  for  the  lodgement  of  the  vertebral  artery. 

\\  liat  is  peculiar  about  tlie  relation  of  the  articular  processes  of  the  axis  and 
atlas  to  (lie  spinal  nerves  f 

In  these  vertebrae  the  nerves  issue  behind  the  articular  processes  ;  the  remain- 
ing spinal  nerves  issue  in  front  of  the  articular  facets  or  processes. 


ARTICULA  TIONS.— LIGAMENTS. 


465 


SEVENTH  CERVICAL  VERTEBRA,  POSTERO- 

SUPERIOR  VIEW. 

I.  Body.  2,  2.  Transverse  processes.  3,  3.  An- 
terior or  costal  roots  of  transverse  processes.  4,  4. 
Foramina  for  vertebral  arteries.  5,  5.  Superior 
articular  processes.  6,  6.  Inferior  articular  pro- 
cesses. 7,  7-  Laminae.  8.  Spinous  process.  9. 
Spinal  foramen. 


DORSAL  VERTEBRA,  ANTEROSUPERIOR  VIEW. 
I.  Anterior   surface.      2.  Vertebral   foramen.      3. 
Spinous  process.      4,  4.    Transverse    processes. 

5,  5.    Articular   surfaces    for   tubercles   of    ribs. 

6,  6.   Superior  articular  processes.      7,  7.   Pedi- 
cles. 


FIRST  DORSAL  VERTEBRA, 

LATERAL  VIEW. 
I.  Superior  surface  of  body.  2,  2. 
Semilunar  processes.  3.  Artic- 
ular facet  for  bead  of  first  rib. 
4.  Demi- facet  for  head  of  second 
rib.  5.  Superior  articular  pro- 
cess. 6,  6.  Inferior  articular 
processes.  7.  Transverse  pro- 
cess. 8.  Articular  facet  for 
tubercle  of  first  rib.  9.  Spin- 
ous process. 


ELEVENTH  DORSAL  VERTEBRA, 
LATERAL  VIEW. 

I.  Articular  facet  for  head  of 
eleventh  rib.  2.  Transverse 
process.  3.  Superior  tubercle 
of  transverse  process.  4.  In- 
ferior and  anterior  tubercle. 
5.  Inferior  and  posterior  tuber- 
cle. 6.  Superior  articular  pro- 
cess. 7.  Inferior  articular  pro- 
cess. 8.  Spinous  process. 

FIG.   337. 


TWELFTH  DORSAL  VERTEBRA, 
LATERAL  VIEW. 

I.  Articular  facet  for  head  of 
twelfth  rib.  2.  Transverse  pro- 
cess. ,  3.  Superior  and  poste- 
rior tubercle  of  transverse  pro- 
cess. 4.  Inferior  and  posterior 
tubercle.  5.  Inferior  and  an- 
terior tubercle.  6.  Superior 
articular  process.  7,  7.  Infe- 
rior articular  processes.  8. 
Spinous  process. 


FIG.  338. — OCCIPITAL  BONE,  POSTERO-INFERIOR  VIEW. 

I,   Basilar  process.     2.  Foramen  magnum.     3,3.   Posterior  condyloid  foramina.     4.   Crest.     5.   External 
occipital  protuberance.     6,  6.   Condyles.     7,  7.  Jugular  processes.     8,  8.   Jugular  fossaj. 


466 


PRACTICAL   ANATOMY. 


Occipito- 

atlantal 

capsular 

ligament 


The  anterior  oblique 
or  lateral  oceipito- 
atlantal  ligament 

Atlanto-axoidean 
capsular  ligament 


Capsular  ligaments  of 
articular  processes 
between  axis  and 
the  third,  the  third 
and  fourth,  and  the 
fourth  and  fifth  cer- 
vical vertebrae 


Continuation  of 
the  anterior 
common  liga- 
ment of  the 
vertebral 
column 

Anterior  oceipi- 
to-atlantal 
ligament 


Anterior  atlanto- 
axoidean  ligament 


BODY  OF  AXIS 


Short  vertebral 
ligament 


Anterior  common 
ligament 


FIG.  339. — ANTERIOR  VIEW  OF  THE  UPPER  KND  OK  THE  SPINE. 


The  interartioular 
ligament 


The  superior  or  anterior 
costo-tranaverse  ligaments 


The  stellate  ligament 


Fro.    MO- — SIIO\VIN<;    THE    ANIIKIHK    COMMON    I.ICAMKNT   OK  THE    SPINE,   AND  THE   CONNECTION 

OK    THE     RlliS     \VITII      I  III      Yl  K  I  I  1 


A  R  TICUL  A  77  6LA  'S.  —L I GA  ME  NTS. 


467 


\Vliat  is  peculiar  about  the  axis  / 

The  odontoid  process,  the  dissociated  body  of  the  atlas,  is  fused  to  the  axis. 
Xatne  the  ligaments  that  bind  the  axis  to  the  atlas. 
These  ligaments  have  to  do  with  two  distinct  classifications  : 

-ri      i   ,       i    ,,  .  ,  f      Class. — Diarthrosis. 

1.  1  he  lateral  atlanto-axoidean  ,,.....  ,. 

(_     Subdivision. — Arthrodia. 

^,  .  ,  f      Class. — Diarthrosis. 

2.  1  he  central  atlanto-axoidean  ...... 

(     Subdivision. —  1  rochoides. 

The    ligaments    are   of  periosteal    derivation,   called:    (i)   Anterior  atlanto- 
axoidean  ;  (2)  posterior   atlanto-axoidean  ;   (3)  two  capsular  ligaments  lined  by 


Left  lateral 
odontoid 
ligament 


Transverse  ligament 


Inner  part  of  capsular  ligament 
of  occipito-atlantal  j  oint 


Posterior  oeeipito-atlantal 
ligament 


Descending  portion  of  crucial 
ligament 


Posterior  atlanto-axoidean 
ligament 


Interspinous  ligament 


Ligamentum  subflavum 


Central  odontoid 

ligament 

Anterior  occipito- 
atlantal  ligament 

Atlanto-odontoid 
synovial  sac 


Anterior  atlanto- 
axoidean  ligament 


FIG.  341. — VERTICAL  ANTERO-POSTERIOR  SECTION  OF  SPINAL  COLUMN  THROUGH  MEDIAN 

LINE,  SHOWING  LIGAMENTS. 

synovial  membrane  ;   (4)  the  transverse  ligament  extending  between  the  tuber- 
cles of  the  lateral  masses  ;    (5)  the  atlanto-odontoid  capsular  ligament. 


THE  ATLANTO-OCCIPITAL  ARTICULATION  AND  LIGAMENTS. 

1.  Class. — Diarthrosis,  because  of  free  movement  and  synovia. 

2.  Subdivision. — Double  condylarthrosis. 

3.  Technical  Name. — Occipito-atlantal,  or  atlanto-occipital. 

4.  Osteological  Units. — Occipital  bone  and  atlas. 

5.  Subdivisions. — Condyles  of  occipital  bone  and  lateral  masses  of  atlas. 


468 


PRACTICAL  ANATOMY. 


6.  Nerve-supply. — Anterior  division  of  the  suboccipital  nerve. 

7.  Blood-supply. — The  vertebral  and  ascending  pbaiyngeal  arteries. 

8.  Ligaments  of  Atlanta-occipital  Articulation. — ( i )  Anterior  occipito-atlantal ; 
(2)  posterior  occipito-atlantal  ;  (3)  two  capsular  ;  (4)  two  anterior  oblique. 

THE  OCCIPITO-AXOID  ARTICULATION  AND  LIGAMENTS. 

1.  The  occipito-cervical. 

2.  The  crucial. 

3.  Two  lateral  odontoid  or  check. 

4.  The  central  odontoid  or  suspensory. 

For   detailed    description    of    these    ligaments    the    student    is    referred    to 
"  Morris'  Anatomy." 


Atlanto-axoid- 
ean  capsular 
ligament 


Occipito-carvl- 
cal  ligament, 
i.e.,  the  deep 
stratum  of  the 
posterior  com- 
mon vertebral 
ligament 


Transverse  process  of  atlas 


FIG.  342. — THE  SUPERFICIAL  LAYER  OF  THE  POSTERIOR  COMMON  VERTEBRAL  LIGAMENT  HAS  I-I-.KN 
REMOVED  TO  SHOW  ITS  DEEP  OR  SHORT  P'lBRES.  THESE  DEEP  FIBRES  FORM  THE  OCC1PITO- 
CERVICAL  LIGAMENT. 


ARTICULATION  OF  THE  Rius  WITH  THE  VERTEBR.I  . 

1.  Class. — Diarthrosis,  because  of  free  movement,  and  a  capsule, 

2.  Subdivision. — Condylarthrosis,  because  of  no  axial  rotation. 

3.  Osteological  Units. — Vertebrae  and  ribs. 

4.  Subdivisions. — Head  and  tubercle  of  rib  ;   body  and  transverse  process. 

5.  Tcclinical  Xanics. — Costocentral  joints  ;  costotransverse  joints. 

6.  Basis  of  Joint. — A  capsule  lined  by  a  synovial  membrane. 

Tin.  BONY  THORAX  AND  ITS  INTRINSIC  LIGAMENTS. 

The  bony  thorax,  plus  certain  soft  parts, — as  ligaments,  fascia-,  muscles,  and 
skin, — is  a  cavity  for  the  protection  of  the  major  organs  of  respiration  and  circu- 
lation. Geometrical  analysis  of  the  thorax  shows  it  to  have  : 

i.   An  'f/V.r,  formed  by  the  manubrium,  first  rib,  first  thoracic  vertebra. 


ARTICULA  TIONS.— LIGAMENTS. 


469 


FIG.  343. — RIBS  OF  LEFT  SIDE,  POSTERIOR  ASPECT. 

1-12.  Anterior  extremities  of  twelve  ribs  of  left  side.  13,  13.  Internal  surface.  14,14.  External  surface. 
15.  Head  of  first  rib.  16.  Mead  of  second  rib.  17.  Head  of  third  rib.  18,  18.  Heads  of  ribs  from 
fourth  to  ninth.  19.  Head  of  tenth  rib.  20,  20.  Heads  of  eleventh  and  twelfth  ribs.  21,  21.  Necks 
of  ribs.  22.  Tubercle  of  first  rib.  23.  Articular  facet  of  tubercle  of  second  rib.  24,24.  Articular 
facets  of  tubercles  of  ribs  from  third  to  ninth.  25.  Articular  facet  for  tubercle  of  tenth  rib.  26,  26. 
Angles  of  ribs. 


FIG.  344. — THORAX,  ANTERIOR  VIEW. 

I.  Manubrium  sterni.  2.  Gladiolus.  3.  Ensiform  cartilage  or  xiphoid  appendix.  4.  Circumference  of 
apex  of  thorax.  5.  Circumference  of  base.  6.  First  rib.  7.  Second  rib.  8,8.  Third,  fourth,  fifth, 
sixth,  and  seventh  ribs.  9.  Eighth,  ninth,  and  tenth  ribs.  10.  Eleventh  and  twelfth  ribs,  n,  n. 
Costal  cartilages. 


470 


PR  A  CT1CAL  ANA  TOM  \ '. 


2.  The  base,  formed  by  the  musculo-aponeurotic  diaphragm. 

3.  An  anterior  wall,  formed  by  the  sternum  and  costal  chondra  or  cartilages. 

4.  A  posterior  wall,  formed  by  the  thoracic  vertebrae  and  the  ribs  to  the  angle. 

5.  Lateral  walls,  formed  by  the  rib  from  angle  to  costo-chondral  joint. 
There  are  twelve  ribs  on  each  side — twenty-four  ribs  in  the  typical  human 

thorax.  Each  rib  articulates  with  the  vertebral  column  posteriorly  ;  the  seven 
upper  ribs  articulate  in  front  with  the  sternum,  being  called,  on  this  account,  true 
ribs.  Of  the  five  lower  ribs,  three  have  their  ventral  end  secured  in  this  manner  : 
the  eighth  is  attached  to  the  cartilage  of  the  seventh,  the  ninth  to  the  cartilage 
of  the  eighth,  the  tenth  to  the  cartilage  of  the  ninth  rib.  The  ventral  ends  of  the 
eleventh  and  twelfth  ribs  are  free, — /.  e.,  unattached, — and  are  called  floating. 
A  typical  rib,  the  seventh,  should  be  studied  systematically  as  to  : 

1.  A  head,  which  has  two  facets  and  a  horizontal  crest. 

2.  A  neck,  which  intervenes  between  the  head  and  the  tubercle. 

3.  Tubercle,  which  consists  of  an  articular  and  a  non-articular  part. 

4.  An  angle,  the  place  where  the  rib  bends  in  two  directions. 

5.  The  Shaft. — This  has  two  surfaces  and  two  borders. 

6.  The  outer  surface  is  for  the  attachment  of  muscles. 


SpinouB  process  of  seventh 
cervical  vertebra 


Capsular  ligament  of  first 
oosto-central  joint 


Capaular  ligament  of  the  flrst  costo-trans- 
verse  joint 

FIG.  345. — THK  CAI-SULAK  I.ICAMKMS  OF  THE  COSTO-VERTEBRAI.  JOINTS. 

7.  The  inner  surface,  has  the  subcostal  groove  for  nerve  and  vessels. 

8.  The  superior  border,  which  is  thick  and  rounded. 

9.  An  inferior  border,  which  is  sharp  and  thin. 

10.   The  subcostal  groove  lodges  the  intercostal  vessels  and  nerves. 

Give  tlic  rule  for  the  articular  part  of  the  head  of  a  rib. 

There  are  two  facets,  separated  by  a  hori/.ontal  ridge.  The  ridge  is  for  the 
attachment  of  the  interosseous  ligament  between  the  rib  and  the  intercentral 
disc  of  fibre-cartilage. 

1 1  'hat  practical  observation  can  be  made  regard in£  flic  lower  articular  facet  on 
(lie  head  of  a  rib  / 

This  one  is  the  larger  of  the  two,  as  a  rule,  and  articulates  with  the  thoracic 
vertebra  which  corresponds  to  it  in  number  from  above  down.  The  upper  i^ 
the  smaller,  and  articulates  with  the  vertebra  next  above. 

Arc  there  anr  c.vccptions  to  the  rule  of  costal  facets  on  the  heads  of  ribs  / 

Yes.  As  exceptions,  may  be  mentioned  the  first,  tenth,  eleventh,  and  twelfth 
ribs,  each  of  which  has  one  facet  only  on  its  head,  as  a  rule. 

Does  the  rib  articulate  with  the  vertebral  column  at  any  other  point !  If  so. 
explain  fully  tlic  rule. 


ARTICULA  riONS.— LIGAMENTS.  47 1 

The  rule  is,  the  articular  part  of  the  costal  tubercle  articulates  with  the  trans- 
verse process  of  the  lower  of  the  two  vertebrae  with  which  the  head  of  the 
rib  articulates  ;  thus,  the  first  articulates  with  the  first,  the  second  with  the 
second,  and  the  third  with  the  third. 

Are  there  any  exceptions  to  tlie  rule  governing  tlie  articulation  of  transverse  pro- 
cesses and  articular  parts  of  costal  tubercles  f 

Yes ;  the  eleventh  and  twelfth  ribs  do  not  articulate  with  the  transverse 
processes. 

Enumerate  tlie  articulations  of  the  ribs  with  the  vertebra. 

(i)  Costocentral,  between  heads  of  ribs  and  bodies  of  vertebrae;  (2)  costo- 
transverse,  between  tubercles  of  ribs  and  transverse  processes. 

COSTOCENTRAL  ARTICULATION — LIGAMENTS. 

1.  Class. — Diarthrosis,  because  of  capsule  and  free  movement. 

2.  Subdivision. — Condylarthrosis,  there  being  absent  axial  rotation. 

3.  Osteological  Units. — A  rib  and  a  vertebra. 

4.  Subdivisionai  Parts. — Head  of  a  rib,  centrum,  and  cartilage. 


Anterior  costo-central 
or  stellate  ligament 


Costo-central  synovial 
sac 


Laminar  portion  of  inter- 
vertebral  disc 


Central  pulpy  portion  of  inter- 
vertebral  disc 


Middle  eqsto-trans- 
verse  ligament 


Costo-transverse  synovial  sao 


Posterior  costo-transverse 
ligament 


FIG.  346. — HORIZONTAL  SECTION  THROUGH  THE  INTERVKRTEBRAL  Disc  AND  RIBS. 

5.  Basis. — A  capsule  lined  by  synovial  membrane. 

6.  Subdivisions. — Interarticular  and  costocentral  or  stellate  ligaments. 
From  what  point  to  what  point  does  the  interarticular  ligament  extend  / 
From  the   interarticular  cartilage  to  the  horizontal  ridge  on  the  head  of  the 

rib,  between  the  articular  surfaces  of  the  same. 

From  wJiat  point  to  wliat  point  does  the  stellate  ligament  extend  / 

From  the  front  of  the  head  of  a  rib,  externally,  to  the  bodies  and  cartilage 
with  which  the  head  articulates. 

Of  liow  many  parts  does  tlie  articulation  between  the  head  of  the  rib  and  the 
centrum  consist  / 

This  cavity  is  divided  into  two  distinct  parts  by  the  interarticular  ligament. 


COSTOTRANSVERSE    ARTICULATION LlGAMENTS. 

Class. — Diarthrosis,  because  of  free  motion  and  a  capsule. 
Subdivision. — Arthrodia,  because  motion  is  simple  and  gliding. 
Osteological  Units. — A  rib  and  a  vertebra. 


472  PRACTICAL   ANATOMY. 

Subdivisions. — Vertebral  transverse  process  and  tubercle  of  a  rib. 
Basis. — A  capsule  lined  by  synovial  membrane. 
Accessory  Ligaments. — Middle,  superior,  posterior,  costotransverse. 
Locate  the  middle  costotransverse  ligament. 


FOR  FIRST  RIB 


An  interarticular 
ligament 


SECOND  RIB 


The  plate  of  flbro- 
cartilage  between 
manubrium  and 
meso  -sternum 


SEVENTH  RIB 


Interohondral 
capaular  ligament 


Fic.  347. — '1'iiK  STERNUM. 
(Left  side,  showing  ligaments;  right  side,  the  synovial  cavities.) 


It  is  between  the  back  of  the  neck  ot  the  rib  and  the  front  of  the  transverse 
process.     It  is  called  the  costotransverse  interosseous  ligament. 
Locate  tlie  posterior  costotransverse  ligament. 

It  extends  from  the  non-articular  part  of  the  tubercle  of  the  rib  to  the  tip  of 

the  trunsvrrsr  prore^. 

Locate  ///(•  superior  costotran.^'ersc  ligament. 


VEINS. 


473 


It  extends  from  the  crest  of  the  neck  of  the  rib  to  the  lower  border  of  the 
transverse  process  of  the  vertebra  next  above. 
Have  all  the  costal  heads  capsules  ? 

No  ;  the  eleventh  and  twelfth  have  none,  their  union  being  fibrous. 
The  anterior  part  of  the  thorax  has  the  following  articulations  : 

1.  Intersternal,  binding  sternal  ligaments  together. 

2.  Costo-chondral,  binding  the  ribs  to  their  cartilages. 

3.  Chondro-sternal,  binding  the  costal  cartilages  to  the  sternum. 

4.  IntercJwndral,  binding  the  sixth,  seventh,  eighth,  ninth,  and  tenth  costal 
cartilages  together. 

The  superior  intersternal  articulation  is  an  ainphiartJirodial.  joint. 

The  manubrium  and  gladiolus  are  bound  together  by  an  anterior  and  a. poste- 
rior common  sternal  ligament  and  by  an  interosseus  fibro-cartilage.  This  ridge  or 
junction  may  be  considered  valuable  in  physical  diagnosis  as  a  guide  to  counting 
the  ribs,  since  it  corresponds  to  the  cartilage  of  the  second  rib. 

The  inferior  intersternal  articulation  is  between  the  gladiolus  and  eusifonti  parts 
of  the  stern n in. 

By  this  union  these  two  pieces  form  a  synarthrodial  joint. 

THE  CHONDRO-STERNAL  ARTICULATION. 

Wherein  does  the  articulation  of  the  first  rib  differ  from  the  others  in  its  articu- 
lation with  the  sternum  /  » 

It  is  synarthrodial ;  the  others  are  diarthrodial,  -the  hinge  or  ginglymoid 
variety. 

Name  the  ligaments  of  the  chondro-sternal  joints. 

1.  Anterior  chondro-sternal. 

2.  Posterior  chondro-sternal. 

3.  Superior  chondro-sternal. 

4.  Inferior  chondro-sternal. 

lixplain  the  nerve-supply  of  the  intrinsic  thoracic  joints. 

(i)  The  costocentral  is  supplied  by  the  intercostal  nerves  ;  (2)  the  costotrans- 
verse  is  supplied  by  intercostal  nerves  ;  (3)  the  chondro-sternal  is  supplied  by  the 
intercostals. 


SOME  INTERESTING  FACTS  ABOUT  VEINS. 

Veins  have  more  extensive  anastomoses  than  arteries. 

Veins  carry  blood  toward  the  heart ;   arteries  from  the  heart. 

Pulmonary  veins  return  aerated  blood  from  the  lungs. 

Systemic  veins  return  CO2  laden  blood  from  the  body  general. 

Veins  are  arbitrarily  classed  as  superficial  and  deep. 

Systemic  veins  terminate  in  the  superior  and  inferior  venae  cavee. 

Superficial  veins  are  located  in  the  superficial  fascia. 

Superficial  veins  communicate  with  deep  veins  through  deep  fascia. 

Deep  veins  accompany  arteries  in  one  and  the  same  sheath. 

The  portal  vein  takes  blood  from  abdominal  digestive  organs  to  liver. 

Visceral  veins  usually  take  the  name  of  the  organ  they  drain. 

Deep  veins  below  the  elbow  and  knee  are  called  venae  comites. 

The  larger  arteries  are  attended  by  one  vein  only. 

Veins  collapse  when  empty  ;  arteries  remain  open. 

Superficial  veins  have  thicker  walls  than  deep  veins. 


474  PRACTICAL  ANATOMY. 

Veins  are  stronger  than  arteries  proportionate  to  their  thickness. 

The  walls  of  veins  arc  thinner  than  those  of  corresponding  arteries. 

The  following  veins  do  not  accompany  arteries  :  The  large  veins  from  bone  ; 
veins  from  the  skull  and  spinal  canal  ;  the  hepatic  veins — these  latter  take  all 
blood  from  the  liver  to  the  ascending  vena  cava. 

The  veins  in  the  lower  are  thicker  than  those  in  the  upper  extremity. 

Some  veins  have  semilunar  valves  formed  by  the  inner  coat. 

The  following  veins  have  no  valves  :  The  facial,  angular,  Vesalian,  and  oph- 
thalmic ;  the  intracranial  veins  and  dural  sinuses  ;  the  hepatic,  renal,  spermatic, 
ovarian,  and  uterine  ;  the  superior  and  inferior  venae  cavae  and  veins  of  bone ; 
the  veins  of  the  whole  portal  system. 

All  veins  have  nutrient  or  trophic  vessels  called  vasa  vasorum. 

Tlie  rule  governing  the  relation  of  veins  to  arteries  is  as  follows  :  Above  the 
diaphragm  veins  are  anterior  to  their  arteries  ;  below  the  diaphragm,  veins  are 
behind  their  arteries,  where  they  are  not  on  the  same  plane.  Exception  to  the 
rule,  the  renal  vessels. 

Name  the  veins  of  the  head  and  neck  and  indicate  any  points  of  special  or  prac- 
tical importance  in  connection  therewith. 

The  occipital  vein  (Fig.  18)  is  the  principal  vein  of  the  posterior  region  of 
the  scalp.  It  perforates  the  trapezius  muscle  and  is  tributary  to  the  deep  cervi- 
cal vein.  It  communicates  by  an  emissary  with  the  lateral  sinus  by  the  mastoid 
foramen.  This  may  explain  the  rationale  of  the  empiric  practice  of  counterirri- 
tation  in  the  region  of  the  mastoid. 

The  common  temporal  vein  (Fig.  18)  communicates  with  the  deep  temporal 
plexus  of  veins  by  the  deep  temporal  vein.  Infection  of  the  region  of  the  scalp, 
drained  by  tributaries  of  this  vein,  may  reach  the  cavernous  sinus  via  the  deep 
temporal  vein,  the  pterygoid  plexus,  and  the  Vesalian  vein.  In  the  parotid  gland 
this  vein  unites  with  the  internal  maxillary  to  form  the  temporo-maxillary  vein. 

The  facial  vein  (Fig.  18)  corresponds  in  distribution  to  its  companion  artery. 
Near  the  angle  of  the  jaw  it  will  be  seen  to  communicate  with  the  external  jug- 
ular vein.  The  vein  is  tributary  to  the  internal  jugular  below  the  jaw;  the  sub- 
maxillary  gland,  the  digastric  and  stylo-hyoid  muscles,  and  the  hypoglossal  nerve 
(Fig.  31)  intervening  between  the  vein  and  its  artery  in  this  locality.  The  most 
important  tributary  of  this  vein  is  the  angular,  which  communicates  with  the 
ophthalmic  vein.  Infection  may  reach  the  cavernous  sinus  via  the  angular 
vein.  (See  p.  151.) 

The  external  jugular  vein  (Fig.  18)  is  the  cervical  continuation  of  the  tem- 
poro-maxillary vein.  It  perforates  the  deep  cervical  fascia  behind  the  middle  of 
the  clavicle,  and  opens  into  the  subclavian  or  into  the  internal  jugular  vein.  The 
special  feature  of  this  vein  is  its  inability  to  collapse  in  the  region  of  the  clavicle. 
The  deep  cervical  fascia  prevents  collapse.  This  inability  to  collapse  renders 
puncture  of  the  external  jugular  vein  liable  to  the  admission  of  air. 

The  internal  maxillary  vein  is  the  companion  of  the  artery  bearing  the 
same  name.  This  vein  returns  blood  from  the  deep  parts  of  the  face,  the  muscles 
of  maturation,  tin-  teeth,  and  the  greater  part  of  the  dura  mater.  The  veins  from 
these  regions  form  a  plexus  called  the  pterygoid.  This  plexus  is  between  the 
temporal  and  external  pterygoid  muscles,  around  the  latter  muscle,  and  on  the 
inner  surface  of  the  internal  pterygoid  muscle.  The  internal  maxillary  vein 
proper  begins  at  this  plexus.  It  unites  with  the  temporal  vein  in  the  parotid 
-land  to  form  the  temporo-maxillary  vein.  (See  p.  151.) 

The  pterygoid  plexus  communicates  with  the  cavernous  sinus  via  the 
vein  of  Ves.ilius  ;  hence  infection  anywhere  in  the  region  of  the  radicals  of  the 
internal  maxiHarv  vein  may  reach  tin-  dural  sinuses  in  the  same  way. 

The  internal  jugular  vein  (Fig.  ;,  i)  he-ins  at  the  ju-ular  foramen.     It  is  in 


VEINS. 


475 


direct  continuation  with  the  lateral  sinus.  It  conveys  all  the  blood  from  the 
brain  that  is  distributed  to  this  organ  by  the  circle  of  Willis.  This  internal  jugu- 
lar vein,  by  its  confluence  with  the  subclavian  vein,  forms  the  innominate — on 
each  side.  In  the  neck  the  vein  accompanies  the  internal  carotid  and  common 
carotid  arteries,  in  the  upper  and  lower  parts  respectively.  At  the  jugular  fora- 
men the  vein  is  in  relation  with  the  ninth,  tenth,  and  eleventh  cranial  nerves, 
which  also  emerge  from  this  jugular  foramen.  This  vein  has  a  pair  of  valves  two 
inches  above  its  terminus. 

THE  INNOMINATE  VEINS. 

Explain  fully  tlie  innominate  or  brachio-ceplialic  veins  on  the  right  and  left  sides. 

These  veins  are  formed  by  the  confluence  of  the  subclavian  and  internal 
jugular  veins.  (Fig.  150.)  The  left  innominate  is  much  the  longer  of  the 
two.  It  crosses  all  the  branches  of  the  second  part  of  the  arch  of  the  aorta, 
both  pneumogastric  nerves,  the  trachea,  and  the  oesophagus.  Tributary  to  it  are 
both  inferior  thyroid  veins.  This  vein  meets  the  innominate  of  the  right  side  to 
form,  with  the  vena  azygos  major,  the  descending  vena  cava. 

VEINS  OF  THE  UPPER  EXTREMITIES. 

These  are  both  deep  and  superficial.  The  deep  veins  in  the  forearm  are  the 
radial  and  ulnar,  two  for  each  artery,  called  radial  and  ulnar  venae  comites  respec- 
tively. They  are  connected  by  transverse  branches,  one  to  the  other.  The  deep 
veins  of  the  forearm  unite  in  the  retiring  angle  of  the  elbow  (cubital  fossa)  to 
form  the  brachial  vein  or  veins. 

The  Brachial  Vein  or  Veins. — This  vein  extends  from  the  bend  of  the 
elbow  to  the  lower  border  of  the  latissimus  dorsi  tendon — i.  e.,  from  the  cubital 
fossa  to  the  base  of  the  axillary  space.  Where  there  are  two  veins  on  each  side 
of  the  artery  they  communicate  freely  with  each  other  and  with  the  superficial 
veins  opposite  to  them  in  the  superficial  fascia.  Sometimes  the  brachial  receives 
the  basilic  vein. 

The  axillary  vein  is  the  continuation  of  the  brachial  through  the  axillary 
space.  This  vein  has  a  valve  in  its  lower  one-third.  It  is  in  very  close  relation 
with  two  axillary  glands,  on  account  of  which  this  vein  is  of  great  surgical  im- 
portance in  the  operation  for  the  removal  of  infiltrated  axillary  lymphatic  glands. 
This  vein  conveys  nearly  all  the  blood  of  the  upper  extremity.  The  axillary  vein 
is  noted  for  the  following  large  and  important  tributaries  which  it  receives  : 

1.  The  circumflex  (anterior  and  posterior). 

2.  The  three  subscapular  veins. 

3.  The  long  thoracic  vein. 

4.  Small  and  numerous  alar  thoracics  from  the  axillary  glands. 

5.  Short  thoracic  veins,  the  highest  in  the  axillary  space. 

6.  The  long  thoracic  or  external  mammary  vein. 

7.  The  acromio-thoracic  or  thoracic  axis  vein  of  Morris. 

The  subclavian  vein  is  the  upward  continuation  of  the  axillary  vein.  It 
unites  with  the  internal  jugular  vein  behind  the  sterno-clavicular  articulation  to 
form  the  innominate  or  brachio-cephalic  vein.  On  the  outer  surface  of  the  first 
rib  it  lies  in  a  depression,  and  is  separated  from  the  subclavian  artery  by  the 
scalenus  anticus  muscle.  In  front  of  the  vein  are  the  clavicle  and  the  subclavius 
muscle.  Tributaries  are  the  cephalic  and  the  external  and  anterior  jugular  veins. 
On  the  left  side,  the  thoracic  duct  opens  into  the  beginning  of  the  innominate, 
between  the  subclavian  and  internal  jugular  ;  on  the  right  side  the  right  lym- 
phatic duct  opens  into  a  corresponding  point  of  the  right  innominate  vein. 

The  superior  vena  cava  is  formed  by  the  confluence  of  the  two  innominate 
veins.  It  begins  near  the  junction  of  the  sternum  and  first  rib  on  the  right  side. 


476  PRACTICAL   ANATOMY. 

It  is  about  three  inches  long.  About  one-half  of  the  vessel  is  in  the  pericar- 
dium. It  returns  practically  all  the  blood  to  the  heart  from  above  the  dia- 
phragm. Its  minor  tributaries  are  the  vena  azygos  major  and  minor  and  the 
pericardiac,  mediastinal,  and  oesophageal  veins.  The  vena  cava  superior  has  no 
valves,  but  its  tributaries  are  provided  therewith.  The  vessel  opens  into  the  right 
auricle  of  the  heart. 

THE  VEINS  OF  THE  LOWER  EXTREMITIES 

Are  but  superficial  and  deep.  The  superficial  veins  are  very  numerous,  anastomose 
quite  freely,  but  only  two  are  of  sufficient  import  to  be  entitled  to  special  names. 
The  general  name  by  which  structures  in  the  superficial  fascia  are  designated  is 
cutaneous  or  superficial.  The  special  names  for  the  two  important  veins  of  the 
lower  extremity  are  :  (i)  Long  saphenous  ;  (2)  short  saphenous. 

The  long  saphenous  vein  begins  at  the  inner  end  of  the  dorsal  arch  of  the 
foot,  passes  in  front  of  the  inner  malleolus,  behind  the  inner  tuberosity  of  the 
tibia  and  the  inner  condyle  of  the  femur,  and  passes  through  the  saphenous 
opening  in  the  fascia  lata  to  become  tributary  to  the  common  femoral  vein. 
Below  the  knee  this  vein  is  attended  by  the  long  saphenous  nerve.  This  vein  has 
valves.  It  communicates  with  venae  comites  in  its  course.  Above  the  knee  its 
tributaries  are  the  superficial  external  pudic,  the  superficial  epigastric,  the  super- 
ficial circumflex  iliac,  and  the  internal  and  external  femoral  cutaneous  veins. 

The  short  saphenous  vein  begins  at  the  outer  end  of  the  dorsal  arch  of 
the  foot,  passes  behind  the  outer  malleolus,  gains  the  mid-line  of  the  leg  pos- 
teriorly, and  pierces  the  popliteal  fascia  to  become  tributary  to  the  popliteal  vein. 
The  deep  veins  of  the  lower  extremity  accompany  the  arteries,  and  take 
the  same  name,  where  there  is  but  one  vein  to  attend  the  artery;  where,  how- 
ever, there  are  two,  as  is  the  case  below  the  knee,  then  the  term  vence  conritcs  is 
used.  About  one  inch  below  Poupart's  ligament  the  common  femoral  vein  is 
formed  by  the  confluence  of  the  superficial  and  deep  femoral  veins.  The  com- 
mon femoral  vein  is  in  the  femoral  sheath,  between  the  common  femoral  artery 
and  the  femoral  canal.  Above  Poupart's  ligament  this  vessel  is  continued 
upward,  under  the  name  of  external  iliac  vein.  Opposite  the  junction  between  the 
sacrum  and  ilium  the  external  iliac  becomes  confluent  with  the  internal  iliac  vein, 
to  form  the  common  iliac  vein. 

The  ascending  vena  cava  is  formed  by  the  confluence  of  the  common  iliac 
veins.  It  begins  opposite  the  fourth  or  fifth  lumbar  vertebra.  It  lies  to  the  right 
of  the  abdominal  aorta.  It  passes  through  a  groove  on  the  posterior  surface  of 
the  liver.  It  passes  through  the  caval  opening  in  the  diaphragm  and  opens  into 
the  right  auricle  of  the  heart.  The  sacra  media  vein  is  the  first  tributary,  the 
hepatic  vein  the  last  tributary,  that  the  vena  cava  receives  in  its  course.  Between 
these  two  extremes  the  tributaries  are  numerous  and  important :  the  lumbar, 
right  spermatic  or  ovarian,  renal,  suprarenal,  and  phrenic.  The  left  spermatic 
\ein  is  tributary  to  the  left  renal,  as  is  also  its  homologue,  the  ovarian. 

The  portal  vein  is  formed  by  the  gastric,  splenic,  superior  mesenteric,  and 
inferior  mesenteric  arteries.  These  veins  have  no  valves.  Blood  coming  from 
the  abdominal  organs  is  laden  with  bile  and  sugar,  both  of  which  are  removed 
In  >m  tin-  portal  blood  by  the  liver.  The  bile  is  stored  up  in  the  gall-bladder  ; 
the  sugar  is  stored  up  as  potential  energy  in  the  hepatic  cells.  The  portal  vein 
enters  the  root  of  tin-  liver,  between  the  hepatic  artery  and  the  common  bile-duct. 


INDEX. 


A. 

Abdominal  walls,  225 

blood-supply,  233 
contents,  246 

review,  248 
function  of,  233 
interior  view,  235 
nerve-supply,  233 
Abscess,  alveolar,  151 
Accelerator  of  penis,  333 
Adjectives,  substantive,  21 
Alcock's  canal,  337 
Anatomical  root  of  the  lung,  207 
Anconeus,  355 

Annular  ligament,  posterior,  348 
Ansa  hypoglossal  nerve-loop,  155 
Antagonism,  anatomical,  18 

law  of,  308 

Anterior  thoracic  nerves,  195 
Antrum  of  Highmore,  116 

analysis,  116 
blood-supply,  117 
Fillebrown  on,  119 
nerve-supply,  117 
opening  for,  118 
Aponeurosis  defined,  25 
Apoplexy,  nose-bleeding  in,  114 
Apposition,  anatomical,  19 
Arachnoid  membrane,  123 

appearance  of,  126 
Arch,  fibrous,  of  gastrocnemius,  377 

of  soleus,  378 
zygomatic,  28 

Arches,  fibrous,  defined,  25 
Arteries,  gluteal,  372 

laryngeal,  superior  and  inferior,  IIO 
popliteal,  369 
posterior  tibial,  383 
sciatic,  372 
Artery,  anterior  tibial,  310 

ascending  pharyngeal,  63 
brachial,  and  relations,  196 
circumflex,  internal,  use  of,  321 
common  carotid,  58 
dorsalis  pedis,  310 
external  carotid,  59 

circumflex,  321 
facial,  6 1 

branches  of,  in  neck,  6 1 
femoral,  316 

branches  of,  320 
inferior  thyroid,  66 
internal  carotid,  59 

mammary,  66 
maxillary,  88 
lingual,  60 
occipital,  6l 
posterior  auricular,  63 
princeps  cervicis,  67        « 


Artery,  profunda  femoris,  520 
subclavian,  64 

branches  of,  65 
superficial  femoral,  branches  of,  321 

temporal,  63 
superior  intercostal,  66 

thyroid,  60 

suprascapular,  66,  359 
vertebral,  and  branches,  68 
Articulations,  421 

acromio-clavicular,  429 
ankle,  445 

atlanto-occipital,  467 
carpal,  437 
chondro-sternal,  473 
coraco-clavicular,  430 
costo-central,  471 
costo-trans verse,  471 
elbow,  432 

femoro-acetabular,  439 
knee,  440 
medio-tarsal,  302 
occipito-axoid,  468 
pelvis,  453 
radio-carpal,  435 
*radio-ulnar,  inferior,  434 
radio-ulnar,  superior,  432 
sacro-coccygeal,  459 
sacro-ischiatic,  457 
sacro-vertebral,  460 
shoulder,  426 
sterno-clavicular,  431 
table  of,  422 
tarsal,  446 

temporo-mandibular,  425 
tibio-fibular,  444 
Arytenoid  muscle,  109 
Ascending  vena  cava,  212 
Auriculo-temporal  nerve,  37 

ventricular  valves,  218 
Axilla,  or  axillary  space,  188,  192 
angles  and  contents  of,  193 
anterior  boundary  of,  192 

thoracic  nerves  in,  195 
apex  of,  bony  boundaries  of,  192 
axillary  artery  and  branches  in,  196 
base  of,  formation  of,  192 
circumflex  nerve  in,  195 
contents  of,  193 
internal  boundary  of,  193 
musculo-cutaneous  nerve  in,  195 
musculo-spiral  nerve  in,  195 
posterior  boundary  of,  192 
subscapular  nerves  in,  195 
systematic  dissection  of,  193 
ulnar  nerve  in,  195 
Axillary  artery  and  vein,  196 

space,  188,  192 
Azygos  uvulae,  98 

477 


478 


INDEX. 


B. 

Back, 374 

accessorius,  405 
arteries  of,  398 
cervicalis  ascendens,  405 
complexus  muscle  of,  394,  405 
erector  spinaa  of,  394,  403 
ilio-costalis,  405 
latissimus  clorsi,  399 
levator  anguli  scapulae,  400 
longissimus  dorsi,  405 
multifidus  spinae,  407 
nerves  of,  397,  409 
rhomboid  muscles  of,  400 
rotatores  spinae,  407 
semispinales  dorsi  and  colli,  396,  407 
serratus  posticus  inferior,  400 
superior,  400 

seventh  layer  of  muscles  of,  407 
simple  movements  of,  395 
sixth  layer  of  muscles  of,  405 
spinalis  dorsi,  405 
splenius  capitis  et  colli,  400 
suboccipital  muscles,  409 
triangle,  409 
superficial  fascia  of,  394 
table  of  muscles  of,  395 
trachelo-mastoid,  405 
transversalis  colli,  405 
trapezius,  398 
twelfth  rib  of,  394 
vertebral  aponeurosis  of,  394,  400 
Biceps,  185 
Bile-duct,  251 
Bladder,  base  of,  338 
Blood-supply  of  the  dura  mater,  131 
Bone  :  clavicle,  inferior  surface,  191 
superior  surface,  188 
eminences  and  depressions  of,  17 
femur,  anterior  view,  327 

posterior  view,  326        . 
hip-bone,  internal  surface,  287 

posterior  view,  325 
humerus,  anterior  view,  184 
mandible,  inner  view,  28 
outer  view,  28 
maxilla,  antrum,  118 

inner  view,  116 
outer  view,  1 17 
metacarpal,  fifth,  base  of,  152 
pisiform,  importance  of,  152 
ribs,  first  and  second,  198 
sacrum,  anterior  view,  290 
scapula,  dorsal  surface,  345 
skull,  norma  basilaris,  30 
farialis,  29 
lateralis,  27 
sagittal  section,  121 
sternum,  199 

styloid  process  of  temporal,  87 
tibia  and  fibula,  anterior  view,  300 
posterior  view,  301 
lurbinated,  113 
tympanum,  133 
ulna  and  radius,  anterior  view,  179 

posterior  view,  353 
unciform,  importance  of,  152 
Brachial  artery,  196 

and  branches,  196 
pli'\us,  77 

l!ra>  lii..  i  rph.ilir,  212 
Jitat  hi<>  i.i'lialU,   185,  348 
I'.iain,  Mood  supply  of",  135 

circle  of  Willis  of,  135 


Brain,  coverings  of,  120 

ganglionic  arteries  of,  136 

quiz  on  blood-supply  of,  137 

removal  of,  125 

structures  seen  on  base  of,  127 

two  systems  of  blood  circulation  of,  137 

Branches  of  abdominal  aorta,  258 

Buccinator  muscle,  93 


C. 

Calcaneum,  posterior  surface  of,  299 
superior  surface  of,  299 
Calvarium,  121 

removal  of,  125 
Capsules,  16 
Cardiac  plexus,  214 

root,  2ii 

Carotid  artery,  common,  58 
external,  59 
internal,  59 

cavernous  stage  of,  131 

petrosal  stage  of,  131 

seen  on  removing  the  brain, 

128 

sheath,  58 
Carpus  and  hand,  exterior  muscles  of,  152 

osteological  points  of,  152 
Cavernous  sinus,  129 
Central  perineal  point,  338 
Cephalic  vein,  189 
Cerebro-spinal  fluid,  124 
Cervical  fascia,  deep,  47 

scheme  of,  48 
third  layer,  57 
plexus,  73 

Chondro-sternal  articulation,  473 
Cinder  in  eye  and  pain,  150 
Circulation,  adult,  218 
foetal,  219 
Circumflex  nerve,  195 

quadrangular  space,  355 
Circumflexus  palati,  98 
Clavicle,  187 
Clavi -pectoral  fascia,  191 
space,  191 

Coccygeus  muscle,  290 
Compound  words,  10 

rule  for,  10 

Compressor  narium,  34 
Constrictor  muscles  of  pharynx,  99 
Cord,  spermatic,  307 
Coronary  artery,  218 
Corrugator  cutis  ani,  331 
supercilii,  34 

Crico-arytenoideus  lateralis  muscle,  no 
posticus  muscle,  no 
Crico-thyroid  muscle,  no 
Crura  penis,  331 
Crus  penis,  dissection  of,  331 


D. 

Deep  cervical  fascia,  second  layer,  53 

upper  attachments  and  special 

names  for,  51 
crural  arch,  236 
epigastric  vessels,  236 
Deltoid  aponcurosi-.  i 

muscle,  189 

Depressor  agents  of  the  lower  jaw,  93 
anguli  oris,  32 
laliii  inferiori-i,  32 


INDEX. 


479 


Depressor  muscles  of  hyoid  bone,  55 

Dermal  muscles,  aural,  41 

grouped,  41 

Descending  vena  cava,  212 

Diaphragm,  285 

Diaphragms  sellse,  121 

Digastric  muscle,  63 

Dilator  naris,  anterior,  34 
posterior,  35 

Dissecting  defined,  19 

Dr.  Loring's  case  reported,  161 

Duct,  nasal,  140 

Stenson's,  31 

Ductus  arteriosus,  211 

Duodenum,  dissection,  252 

Dura  mater,  121 

arteries  of,  123 
nerves  of,  123 
sinuses  of,  122 


E. 

Emissary  structures,  tabulated  list  of,  151 
Eustachian  tube,  102 

muscles  attached  to,  103 
External  oblique  muscle,  230 


F. 

Face,  osteological  points  of,  29 
Facial  anastomotic  blood  areas,  42 
artery,  38 
nerve,  30 

communication  of,  on  the  face,  37 
dissection  of,  36 
divisions  and  branches,  37 
escape  of,  43 

not  the  cause  of  toothache,  43 
Falx  cerebelli,  122 
cerebri,  122 

dissection  of,  126 
Fascia,  22 

cribriform,  309 
cubital,  24 
deep,  23 

associated  with  muscles,  24 
attachments  of,  308 
forming  intermuscular  septa,  24 
gives  origin  and  insertion  to  muscles, 

308 

in  surgical  areas,  24 
minor  details  of,  308 
of  thigh,  307 
on  back  of  carpus,  348 
dorsal,  23 

in  foot,  24 
iliac  and  pubic,  308 
in  the  upper  extremity,  23 
lata,  23 

subdivisions  of,  308 
of  Colles,  338 
of  lower  extremity,  23 
palmar,  23 

pelvic,  special  names  for,  24 
plantar,  24 
popliteal,  24 
special  names  for,  23 
superficial,  23 

characters  of,  25 
of  lower  extremity,  302 
Female  generative  organs,  291 
Femoral  canal,  236 
fossa,  236 


Femoral  hernia,  238 
ring,  237 
sheath,  236 
Fibula,  anterior  surface  of,  298 

bony  parts  of,  of  interest,  298 
external  surface  of,  298 
internal  surface  of,  298 
posterior  surface  of,  298 
Fillebrown  on  opening  for  antrum,  119 
Fissures  of  brain  and  their, contents,  139 
Flexor  longus  pollicis,  184 

profundus  digitorum,  182 
Foot  and  ankle,  298 

bony  parts  of,  of  interest,  298 
and  leg,  297 
dorsal  arch  of,  303 
long  saphenous  vein  of,  305 
nerve  of,  external  cutaneous,  307 
long  saphenous,  305 
middle  cutaneous,  306 
musculo-cutaneous.  306 
short  saphenous,  306 
short  saphenous  vein  of,  305 
Foramen,  infra-orbital,  41 
mentale,  41 
of  Winslow,  251 
Foramina  at  base  of  skull,  128 

nutrient,  of  bone,  rule  for,  171 
of  Key,  Retzius,  Magendie,  124 
Forearm,  arteries  and  veins  of,  171 
biceps  of,  185 
bones  of,  1 68 
brachialis  anticus  of,  185 
cubital  fossa  of,  172 
flexor  longus  pollicis  of,  184 

profundus  digitorum  of,  182 
sublimis  digitorum  of,  179 
flexors  of,  185 
median  nerve  of,  181 
muscles  of,  physiologically  grouped,  171 
nerves  of,  grouped,  171 
pronator  quadratus  of,  184 
radial  artery  of,  179 
groove  of,  172 
supinator  longus,  185 
surgical  areas  of,  171 
ulnar  artery  of,  177 
groove  of,  173 
nerve  of,  182 
Frown,  complete,  42 

G. 

Ganglion,  otic,   91 

subtnaxillary,  90 
Gasserian  ganglion,  129 

description  of,  131 
Genio-hyo-glossus  muscle,  8l 
Geometrical  terms  and  figures,  2O 
Gland,  lachrymal,  139 

location  of,  147 
thyroid,  57 

Glands,  Pacchionian,  125 
Grooves  for  flexor  longus  hallucis,  299 


H. 

Hallucis,  extensor  proprius,  312 
Hand,  anterior  annular  ligament,  162 

attachment  of,  167 
perforating  arteries  in,  166 
articular  nerves  of,  and  rule,  167 
blood-supply  of,  1 68 
bones  of,  152 


480 


INDEX. 


Hand,  carpal  arteries  in,  166 

cutaneous  nerves  of,  155 
deep  fascia  of,  157 

palmar  arch  of,  1 68 

branch  of  ulnar  nerves  in,  165 
dissection  of,  158 
flexor  tendons  of,  159 
hypothenar  group  of  muscles  of,  164 
infection  of  fingers  of,  167 
median  nerve  in,  and  dissection  of,  162 
palmar  fascia  of,  159 

interossei  muscles  of,  165 
radial  artery  in,  166 
sensory  nerves  of,  167 
superficial  arch  of,  168 
surgical  areas  in  fingers  of,  167 
thecne  of,  160 
thecal  culs-de-sac  of,  160 
tlienar  group  of  muscles  of,  162 
ulnar  artery  in,  166 

nerve  in,  and  dissection  of,  162 
Hepatic  artery,  251 
Hesselbach's  triangle,  233 
Highmore,  antrum  of,  116 

analysis  of,  116 
blood-supply,  117 
drainage  of,  117 
nerve-supply,  117 
opening  for,  118 
Hilton's  law,  19 

Humerus,  bicipital  groove  and  lip  of,  171 
external  condylar  ridge  of,  171 
fracture  in  middle  third  of,  171 
muscles  and  ligaments  attached  to,  171 
nutrient  foramen  of,  171 
osteology  of,  170 
outer  and  inner  surfaces  of,  171 
posterior  surface  of,  171 
relation  of,  to  musculo-spiral  nerve,  171 
Hunter's  canal,  323 
Hyo-glossus  muscle,  64 
Hyoid  bone,  movements  of,  80 
Hypogastric  plexus,  273 
Hypoglossal  nerve,  63 


I. 

Iliac  artery,  internal,  278 

fascia,  275 

Iliacus  muscle,  279,  289 
Ilio-hypogastric  nerve,  235 
Ilio-inguinal  nerve,  235 
Inferior  mesenteric  artery,  257 
Inguinal  canal,  analysis,  230 
fossa,  236 
hernia,  234 
Innominate  veins,  475 
Intercostal  fascia,  201 
muscles,  201 
nerves,  201 

Interior  of  thorax,  204 
Int. TIKI]  abdominal  ring,  236 
cutaneous  nerve,  195 
mammary  artery,  204 
ol'!i(|ue  muscle,  231 
Intestin.-,  |:,rg.-  and  small,  248 
Ischio-rectal  fossa,  279 


J- 

Jugular   vein,  internal,  vS 

superficial,  46 

Ju\t;i.    1   ; 


K. 

Kidney,  descriptive  terms  of,  260 
left,  relations  of,  259 
right,  relations  of,  258 
root-structures  of,  259 
ureter  of,  292 

Knee-joint,  440 

ligaments  of,  442 


L. 

Larynx,  106 

arytenoid  cartilage  of,  108 

muscle  of,  109 
blood-supply  of,  1 10 

crico-arytenoideus  lateralis  muscle  of,  no 
posticus  muscle  of,  no 
cricoid  cartilage  of,  108 
crico-thyroid  muscle  of,  1 10 
false  vocal  cords  of,  109 
inferior  laryngeal  nerve  of,  109 
retiring  angle  of,  108 
superior  laryngeal  nerve  of,  109 
thyro-arytenoid  muscle  of,  109 
thyroid  cartilage  of,  107 
true  vocal  cords  of,  109 
Latissimus  dorsi,  196 
Law  of  projectiles,  21 
Levator  anguli  oris,  32 

scapulae,  69 
ani,  291 
labii  superioris,  32 

akeque  nasi,  33 
menti,  34 
palati  muscle,  98 

Ligament,  anterior  annular,  at  the  wrist  and  struc- 
tures under,  162 
(foot),  23 
relations,  162 
external  annular,  24 
interior  annular  (hand),  23 
internal  annular,  24 
posterior  annular,  23 
Ligamenta  vaginales  of  foot,  24 

of  hand,  159 

Ligamentum  vaginale,  23 
Liver,  253 

arteries  and  nerves  of,  255 
foetal  remains  of,  255 
how  described,  256 
ligaments  of,  253 
root-structures  of,  251 
Longus  colli  muscle,  104 
Lumbar  plexus,  275 
Lymphatics  of  neck,  superficial,  46 


M. 
Mandible,  29 

Irv.ilors  ;m<l  depressors  of,  93 
muscles  concerned  in  dislocation  of,  96 
Masseter  muscle,  49 

superficial  and  deep  parts  of,  93 
Meckel's  fascia,  space,  cave,  151 
Median  nerve,  182 
Mediastinal  spaces,  208 
Membranes,  mucous,  character  of,  26 
serous,  diameter  of,  25 
Mimual,  character  of,  26 
Meningral  artc-iy,  middle,  130 
Mrnin^c.-,.  121 

Mouth,  study  nf,  on  cadaver,  79 
on  living,  711 


INDEX. 


481 


Muscles,  abductor,  of  thigh,  377 
accelerator  urinse,  333 
adductor  longus,  315 

of  thigh,  377 
anconeus,  355 
aponeurosis  of,  25 
arising  from  styloid  process,  85 
biceps,  185 
brachialis  anticus,  185 
brachio-radialis,  185,  348 
compressor  narium,  34 
corrugator  supercilii,  34 
deltoid,  189,  335 
depressor  anguli  oris,  32 

labii  inferioris,  32 
depressors  of  the  hyoid  bone,  56 
digastric,  63 
dilator  naris,  anterior,  34 

posterior,   35 
dorsal  interossei,  354 
erector  penis,  333 
extensor  brevis  digitorum,  310 

pollicis,  351 

carpi  radialis  brevior,  349 
longior,  349 
ulnaris,  350 

communis  digitorum,  350 
indicis,  351 
longus  digitorum,  312 

pollicis,  351 
minimi  digiti,  350 
of  thigh,  377 

ossis  metacarpi  pollicis,  351 
proprius  hallucis,  312 
external  oblique,  229 
pterygoid,  83 
fanciful  names  for,  19 
fibrous  arches  of,  25 
flexor  carpi  radialis,  176 

longus  digitorum,  384 

hallucis,  grooves  for,  384 
of  thigh,  377 
profundus  digitorum,  182 
sublimis  digitorum,  179 
forming  musculatures,  25 
genio-hyo-glossus,  8 1 
gluteus  maximus,  370 
medius,  371 
minimus,  371 
gracilis,  315 
hyo-glossus,  64 
hypothenar  group  of,  164 
iliacus,  279,  289 
infraspinatus,  358 
in  movements  of  hip,  377 
in  region  of  shoulder,  355 
intercostal,  200 

external,  200 
internal,  201 
internal  oblique,  231 
pterygoid,  83 
interossei,  dorsal,  362 
involuntary,  14 
latissimus  dorsi,  196,  356 
levator  anguli  oris,  32 

scapulae,  69 
ani,  291,  332 
labii  superioris,  32 

alseque  nasi,  33 
menti,  34 
longus  colli,  105 
masseter,  49 
mylo-hyoid,  81 

relations  of,  82 


Muscles,  obturator  externus,  289 

internus,  289,  279 

dissection  of,  375 
occipito-frontalis,  120 
of  anterior  surface  of  fibula,  310 
of  facial  expression,  35 
of  forearm,    anterior  and   radial,   physio- 
logically grouped,  171 
of  leg,  deep,  384 
of  mastication,  93 

nerve-supply,  96 
of  the  eyeball,  145 
of  the  larynx,  109,  no 
of  the  orbit  and  their  function,  149 
of  the  pharynx,  99 
of  the  soft  palate,  98 
orbicular  and  sphincter,  19 
orbicularis  oris,  33 

palpebrarum,  33 
origin  and  insertion  of,  25 
palato-glossus,  action  of,  85 
palato-pharyngeus,  86 

paralysis  of,  86 
palmar  interossei,  165 
palmaris  brevis,  161 
longus,  176 
pectoralis  major,  189 
minor,  191 
peronei,  384 
peroneus  tertius,  315 
physiological  adductor,  328 
plantaris,  377 
platysma  myoides,  45 
pronator  quadratus,  184 
radii  teres,  177 
psoas  magnus,  288 

relations,  275 
parvus,  289 
pyramidalis,  232 

nasi,  34 

pyriformis,  289,  372 
quadratus  lumborum,  287 
radial  group  of,  349 
rationale  of  naming,  n 
rectus  abdominis,  232 

capitis  anticus  major,  103 
minor,  104 
femoris,  317,  325 
rotator,  external,  377 
internal,  377 
sartorius,  315 
scaleni,  68,  200  , 

origin  of,  69 
semimembranosus,  369 
serratus  magnus,  196 
shape  of,  1 8 

index  to  nerve-supply,  18 
sphincter  and  orbicular,  19 

distinguished,  2O 
sterno-mastoid,  50 

relations,  52 
stylo-glossus,  82 
stylo-hyoid,  82 
subclavius,  191,  200 
subscapularis,  196 
substantive  adjectives  of,  21 
supinator  longus,  349 

radii  brevis,  354 
longus,  348 
supraspinatus,  358 
synonymous  usage  of,  19 
temporal,  50 
teres  major,  196,  356 
minor,  356 


482 

Muscles,  thenar  group  of,  162 

tibialis  anticus,  310 

transversalis,  232 

colli,  68 

transversus  perinsei,  334 

triangularis  sterni,  204 

triceps,  359 

under  anterior  annular  ligament,  102 
posterior  annular  ligament,  348 

vasti,  internus,  externus,  318,  325 

zygomatici,  major  and  minor,  33 
Musculature  defined,  25 
Mtisculi  lingualis,  82 

lumbricales,  162 


N. 
Nasal  fossae,  1 1 1 

arteries  of,  114 
geometry  of,  ill 
hemorrhage  of,  114 
meatuses  of,  113,  116 
mucous  membrane  of,  113 
nerve-supply  of,  115 
turbinated  bones  of,  113 
Neck,  boundaries  of,  44 
dissection  of,  43 
jugular  veins  of,  46 
lymphatic  T  of,  46 
quiz  on,  48,  49,  55,  56,  57 
surgical  and  medical  areas  of,  44 
triangles  of,  44 
Nerve,  abducens,  description  of,  149 

anterior  thoracic,  in  the  axilla,  195 

tibial,  310 
auditory,  416 
chorda  tympani,  90 
circumflex,  361,  363 

in  the  axilla,  195 
cranial,  classification,  410 
origin  of,  410 
summary,  410 

cutaneous  branches  of  external  plantar,  387 
of  internal  plantar,  387 
of  lower  extremity,  365 
of  upper  extremity,  155 
eighth  cranial  auditory,  128 
eleventh  cranial,  128 
endings,  26 
external  popliteal,  367 
facial,  415 

dissection  of,  in  the  petrosa,  135 
fifth  cranial, — trigeminus,  128 
fourth  cranial, — patheticus,  128 
frontal,  description  of,  148 
glosso-pharyngeal,  92,  416 
gluteal,  superior,  372 
great  sciatic,  372 
hypoglossal,  63,  426 
ilio-hypogastric,  365 
inferior  gluteal,  373 
infi:i-orbital,  31,  1 10 
internal  cutaneous,  in  the  axilla,  195 

pudic,  374 

lachrymal,  description  of,  148 
l;u yngeal,  superior  and  inferior,  109 
lesser  internal  cutaneous,  in  tin-  axilla,  195 
long  saphenous,  366 
median,  362 

symptoms  in  paralysis  of,  167 
ment 
niotm  .MII 

description  of,  148 
musculo-cutaii'  :         ^63 


INDEX. 


Nerve,  musculo-cutaneous,  in  the  axilla,  195 
musculo-spiral,  195,  361,  363 

in  the  axilla,  195 
mylo-hyoid,  87 
nasal,  145 

description  of,  148 
distribution  of,  118 
ninth  cranial,  128 
olfactory,  411 

distribution  of,  118 
optic,  412 

description  of,  149 
patheticus,  413 

description  of,  148 
phrenic,  69 

plantar,  cutaneous,  387 
external,  392 
internal,  392 

pneumogastric,  branches  of,  in  the  neck,  58 
popliteal,  internal,  378 
posterior  interosseous,  362 

tibial,  379,  382 
seventh  cranial,  facial,  128 
short  saphenous,  369 
sixth  cranial,  128 
small  sciatic,  366,  372 
spinal  accessory,  45,  417 

ganglia  of,  410 

subscapular,  in  the  axilla,  195 
supraorbital,  31 
suprascapular,  361 
tenth  cranial,  128 
tibial,  posterior,  379 
trifacial,  413 
twelfth  cranial,  128 

thoracic,  365 
ulnar,  362 

in  the  axilla,  195 
symptoms  in  paralysis  of,  167 
vagus,  411,  417 

root-ganglion,  411 
trunk-ganglion,  411 

Noise,  cracking,  in  temporo-mandibular  joint,  96 
Nomenclature,  9 

grammatical  note  on,  12 


O. 

Obturator  externus  muscle,  289 
fascia,  275 

internus  muscle,  279,  289 
Occipito-frontalis  muscle,  120 
Ocular  muscles,  table  of  origin  of,  145 
OZsophagus,  216 
Opposites,  anatomical,  10 
Orbicularis  oris,  33 

antagonists  of,  1 1 
palpebrarum,  33 
Orbit,  angles  of,  140 
contents  of,  141 
dissection  of,  141 
geometry  of,  139 
lachrymal  gland  of,  139 
muscles  of,  and  their  function,  149 
nasal  duct  of,  140 
nerves  of  strut  -lures  seen  in,  149 
ophthalmic  artery  of,  145 

vein  of,  and  its  physiological  an< 
pathological  importance,  150 
periosteum  of,  141 
trochlea  of,  140 
Ovarian  artery,  294 


INDEX. 


483 


P. 


Pacchionian  bodies  and  vHli,  126 

glands,  125 

Pain,  classification  of,  266 
reflex  motor,  268 

rationale,  268 
sensory,  268 
somatic,  266 
sympathetic,  266 

table  of  common  diseases  showing,  266 
transmission  of,  266 
Palate,  soft,  analysis  of,  98 

how  formed,  85 

Palato-glossus  muscle,  action,  85 
Palato-pharyngeus  muscle,  86 

paralysis  of,  86 
Pancreas,  252 
Paralysis  of  median  nerve,  symptoms,  168 

of  ulnar  nerve,  symptoms,  167 
Parotid  fascia,  40 

gland,  contents  of,  40 

excretory  duct,  40 
explanation  of,  43 
limitations  of,  40 
Patella,  298 

reflex,  284 

rationale  of,  285 
Patient's  eye,  150 
Pectoralis  major  muscle,  189 
minor  muscle,  191 
Pelvic  fascia,  275,338 
outlet,  330 

anterior  triangle  of,  330 

dissection  of,  333 

external  sphincter  ani  muscle  of,  332 

female,  340,  341 

greater  sacro-sciatic  ligament  of,  332 

hsemorrhoidal  arteries  of,  332 

ischio-rectal  fossa  in,  336 

levator  ani  muscle  of,  332 

posterior  triangle  of,  330 

superficial  fascia  (Colics')  of,  331 

transversus  perinaei  muscle 

of,  332 

tendinous  centres  of,  332 
triangular  ligaments  of,  336 
white  line,  291 
Pelvis,  deep  dissection  of,  286 

dissection  of,  274 
Penis,  accelerator  of,  333 

blood-supply  of,  339 
bulb  of,  331 
crura,  331 

cms,  dissection  of,  333 
dissection  of,  334 
nerve-supply  of,  340 
Peri-,  13 
Pericardium,  210 
Periosteum  and  its  functions,  17 
Peritoneum,  238 

blood-supply  of,  239 
cavities  of,  252 
investing  organs,  240 
review  of,  239 
Peroneus  brevis,  299 
longus,  299 

Phalanges,  palmar  surface  of,  153 
Pharynx,  99 

attachments  of,  103 
nerve-supply  of,  103 
Phlebotomy,  166 
Pia  mater,  composition  of,  127 
Pituitary  membrane,  113 


Platysma  myoides,  45 
Plexus,  brachial,  77 

cervical,  ascending  branches,  45 
descending  branches,  46 
explanation  of,  73 
superficial  branches,  45 
infra-orbital,  42 
vesico-prostatic,  339 
Plica  hypogastrica,  236 

urachi,  236 

Pneumogastric  nerve,  217 
Popliteal  nerve,  external,  284 
internal,  283 
Portal  vein,  252 
Posterior  mediastinum,  215 
Poupart's  ligament,  323 
Pre-,  13 

Prepositions,  technical  use  of,  12 
Projectiles,  application  of  law  of,  22 

law  of,  21 

Pronator  quadratus  muscle,  184 
Prostate  gland,  339 
Psoas  magnus,  288 

relations  of,  275 
parvus,  289 

Pterygoid  muscle,  external,  87,  95 
internal,  87,  93 
plexus,  151,  474 
Pudic  nerve,  internal,  282 
Pulmonary  artery,  211 

trio,  207 

Pus  from  carious  tooth,  151 
Pyramidalis  nasi,  34 
Pyriformis  muscle,  289 


R. 

Radial  nerve,  355 

oblique  line,  185 
Radius,  osteology  of,  1 68 
Rectum,  275 

Rectus  capitis  anticus  major  muscle,  103 
minor  muscle,  104 

muscle,  232 

Reflex  pain,  primary  and  secondary,  92 
Region  of  shoulder,  355 
Rib,  typical,  201 
Roots,  anatomical,  17 
Root-structures  of  liver,  251 


S. 

Sacral  plexus,  280 

branches  of,  281 
Salivary  system,  98 
Salpingo-pharyngeus  muscle,  103 
Saphenous  opening,  309 
Scaleni  muscles,  68,  201 

scheme  of  origin  of,  69 
Scapula,  186 

anterior  lip  of  vertebral  border  of,  187 
fracture  of  surgical  neck  of,  187 
middle  lip  of  axillary  border  of,  187 

vertebral  border  of,  187 
osteology  of,  186 
Scapular  fossae,  three,  186 

spine,  lips  of,  187 
Scarpa's  triangle,  322 
Scheme  for  deep  cervical  fascia,  190 
Sciatic  nerve,  greater,  283 

lesser,  283 
Semilunar  fold  of  Douglas,  225 

valves,  218 
Seminal  vesicles,  338 


484 


INDEX. 


Serratus  magnus  muscle,  196 
Sheaths,  anatomical,  16 
carotid,  58 
of  rectus  muscle,  225 
rationale  of  formation  of,  1 6 
Shoulder,  186 

cephalic  vein  of,  189 
clavi-pectoral  fascia  of,  191 
costo-coracoid  ligament  of,  191 
deltoid  aponeurosis  of,  189 

muscle  of,  189 

pectoralis  major  muscle  of,  189 
minor  muscle  of,  191 
subclavius  muscle  of,  187 
Sinus,  cavernous,  and  contents,  129 

superior  longitudinal,  126 
Skull,  base  of,  31 

fissures  of,  31 

Sole  of  foot,  arterial  arch  of,  392 
deep  fascia  of,  388 
external  plantar  artery  of,  392 
internal  plantar  artery  of,  392 
granular  fat  of,  390 
ligamenta  vaginales  of,  391 
lumbricals  of,  393 
muscles  of,  386,  390 

of  first  layer  of,  392 
plantar  fascia  of,  390 
theca  and  thecal  culs-de-sac  of,  391 
Some  interesting  facts  about  veins,  473 
Spermatic  cord,  307 

Spinal  accessory  nerve,  how  distinguished  in  surgi- 
cal operations,  45 
Splanchnic  nerves,  216 
Splenic  artery,  252 
Stenson's  duct,  course  of,  45 
Sterno-cleido-mastoid  muscle,  50 

nerve-supply,  51 
relations  of,  52 
sheath,  50 
Sternum  and  ribs,  inner,  202 

ribs,  and  articulation,  198 
Stomach,  253 
Stylo-glossus  muscle,  82 
Stylo-hyoid  muscle,  82 
Styloid  process,  87 
Sub-,  12 

Subarachnoid  fluid,  123 
space,  123 

special  features  of,  124 
Subclavian  artery,  branches  of,  65 
Subclavius  muscle,  200 

and  sheath,  19! 

Subdural  space,  contents  of,  126 
Subscapular  nerves,  195 
Summary  of  peritoneal  considerations,  246 
Superior  mesenteric  artery,  256 

vena  cava,  475 
Supinator  longus,  348 
Supra-,  13 

Supraorbital  foramen,  139 
Suprascapular  artery  and  nerve,  359 
Supraspinatus,  358 
Surgical  areas  : 

Alcock's  canal,  337 
Anastoni'  :  face,  42 

Antnun  (it    I  lighmore,  the,  Il6 
Auditory  canal,  92 
Axillary  artery,  the,  196 

<-.  the,  188,  192 
Pile  ducts,  the,  251 
Piaeliial   uti-iv,  tin-,   196 

nil  ami  appendix,  the,  248 
<  'alvarium.  llir.  121 
i. 


Surgical  areas : 

Colics'  fascia,  331 
Cribriform  fascia,  the,  309 
Cubital  fossa,  the,  172,  174 
Deep  palmar  arch,  168 
Dislocation  of  jaw,  96 
Emissary  foramina  and  their  veins,  150 
Eustachian  tube,  102 
Face,  the,  151 
Facial  nerve,  the,  135 
Fascia,  deep,  of  upper  extremity,  363 
Female  pelvic  outlet,  the,  340 
Femoral  fossa,  the,  236 
ring,  the,  237 
sheath,  the,  236 
Fingers,  167 
Foramen  of  Winslow,  the,  251 

sacro-sciatic.  greater,  372 

lesser,  373 

Fossa,  cubital  contents,  364 
Gasserian  ganglion,  the,  129 
Geometrically  considered,  20 
Glandulae  concatenatae,  58 
Groove  for  flexor  longus  hallucis,  384 
for  posterior  tibial  artery,  383 
radial,  contents,  363 
ulnar  contents,  363 
Hesselbach's  triangle,  233 
Hunter's  canal,  323 
Hymen,  the,  341 
Inguinal  canal,  the,  230 
Intramural  sinuses,  the,  115 
Ischio-rectal  fossa,  279,  336 
Kidneys,  posterior  relations,  259 

right,  anterior  relations,  258 
root-structures,  259 
Larynx,  the,  1 06 
Ligaments,  internal  annular,  384 
Liver,  the,  253 

Long  saphenous  vein,  the,  305 
Male  urethra,  the,  339 
Median  basilic  vein  in  venesection,  167 
Middle  meningeal  artery,  the,  130 
Nasal  duct,  the,  140 

fossae,  the,  III 
Neck,  boundaries  of,  the,  44 

surgical  areas  of,  the,  44 

triangles  of,  the,  44 
Orbit,  the,  139 
Paralysis  of  median  nerve,  168 

ulnar  nerve,  167 

Parotid  gland,  location  by  limitation,  40 
Pelvic  outlet,  the,  337 
Perineal  body,  the,  343 
Peritoneal  cavities,  the,  252 
Peritoneum,  the,  238 
Popliteal  space,  366 
Posterior  tibial  canal,  383 
Poupart's  ligament,  323 
Prostate,  the,  339 
Quadrangular  space,  the,  356 
Radial  groove,  the,  172 
Reflex  pain,  primary  and  secondary,  92 
Root-structures  of  liver,  251 
Saphenous  opening,  the,  309 
Scarpa's  triangle,  322 
Septic  thrombi  in  alveolar  abscess,  151 

in  erysipelas  of  the  face, 
Soft  palate,  the,  99 
Spermatic  cord,  the,  231 
Stomach,  the,  253 
Superlicial  palmar  aivh.  i"S 
Table  of  pain  in  o.mimm  diseases,  266 
Thecal  culs-de-sac,  the,  161 
Trachea,  the,  no 


INDEX. 


485 


Surgical  areas : 

Triangular  space,  the,  355 
Tympanum,  the,  131 
Ulnar  groove,  the,  173 
Sustentaculum  tali,  299 
Sympathetic  nerve,  261 

essentials  of,  271 
in  abdomen,  270 


T. 

Table  of  origin  of  ocular  muscles,  145 
Tarso-metatarsal  joint,  302 
Temporal  muscle,  5°>  93 

ridge,  complete,  27 
Temporo-mandibular  articulation,  97 
Tendo  oculi,  140 
Tentorium  cerebelli,  122 
Teres  major,  196 

and  latissimus  dorsi,  356 
minor,  356 

Thigh,  fascial  septa  of,  328 
Thoracic  aorta,  213 

duct,  213,  216 
gangliated  cord,  216 
viscera,  posterior  view,  214 
Thorax,  198 

anatomical  root  of  lung,  207 
ascending  vena  cava,  212 
brachio-cephalic  veins,  212 
cardiac  and  pulmonary  plexuses,  214 

root-structures,  211 
clavi-pectoral  fascia  of,  200 
contents  of  anterior  mediastinum,  208 
of  middle  mediastinum,  209 
of  posterior  mediastinum,  209 
descending  vena  cava,  212 
ductus  arteriosus,  211 
geometry  of,  204 
hydro-thorax,  pneumo-thorax,  pyo-thqrax, 

pyo-pneumo-thorax,  206 
inner  surface  of  sternum  and  ribs,  202 
intercostal  muscles  and  fasciae  of,  200 

nerve,  typical,  2OI 
internal  mammary  artery,  204 
mediastinal  spaces  of,  208 
posterior  view  of  viscera,  214 
pulmonary  artery,  211 
scaleni  muscles,  200 
subclavius  muscle,  200 
subdivisions  of,  205 
Thrombi,  septic,  151 
Thymus  gland,  211 
Thyro-arytenoid  muscle,  109 
Thyroid  gland,  157 
Tibia  and  semi-membranosus,  297 
articular  surfaces  of,  297 
bony  parts  of  interest  of,  297 
internal  malleolus  of,  298 

surface  of,  297 
oblique  line  of,  298 
posterior  surface  of,  297 
vertical  line  of,  298 
Tibialis  anticus,  insertions  of,  299 
posticus,  insertions  of,  299 

small  insertion  of,  299 
Tissues,  anatomical,  13 
connective,  14 

forms  of,  14 
constituents  of,  15 
muscular,  13 
Tissues,  nerve,  14 

resume  of,  16 


Tongue,  dissection  of,  79 

movements  of,  8 1 
Tonsil,  87 

Toothache  in  the  ear,  92 
Trachea,  no 

blood -supply,  ill 
nerve-supply,  in 
relations  of,  III 
structure  of,  I IO 
Transversalis  muscle,  232 
Triangular  space,  355 
Trituration,  muscles  of,  93 
Tubercles,  supra-  and  infra -glenoid,  186 
Tympanum,  or  middle  ear,  131 
dissection  of,  135 
facial  nerve  in  relation  to,  133 
geometric  analysis  of,  132 
importance  of,  132 
Typical  rib,  osteology  of,  201 

U. 

Ulna,  anterior  surface  of,  169 
internal  surface  of,  169 
osteology  of,  169 
posterior  surface  of,  169 
vertical  line  of,  170 
Ulnar  nerve,  182,  195 

paralysis  of,  167 
Urethra,  334 

V. 

Veins,  angular  and  ophthalmic,  39 
axillary,  475 
brachial,  475 

cephalic,  at  the  shoulder,  166 
in  venesection,  166 
cerebral,  126 

classification  of,  138 
common  temporal,  474 
communication  between  the  superficial  veins 

and  the  deep  veins,  166 
external  jugular,  474 
facial,  6l,  474 
innominate,  475 
internal  maxillary,  474 
jugular,  internal,  58,  474 
long  saphenous,  476 
median,  156 
occipital,  474 
of  the  face,  39 
of  the  lower  extremity,  476 

deep,  476 

of  the  upper  extremity,  475 
portal,  476 
radial,  155 

some  interesting  facts  about,  473 
subclavian,  64,  475 
superficial,   of  forearm,  155 
termination  of  ulnar,  median,  radial,  166 
ulnar,  156 
Vena  azygos  major,  216 

cava,  ascending,  212,  476 
descending,  212 
superior,  475 
Venae  comites,  166 
Venesection,  criminal  liability  in,  167 
Vesiculse  seminales,  339 
Vestibule  of  oral  cavity,  85 
Vincula,  161 

Viscera,  posterior  view  of,  214 
Vocal  cords,  true  and  false,  109 

W. 

Winslow,  foramen  of,  251 


DATE   DUE  SLIP 

UNIVERSITY  OF  CALIFORNIA  MEDICAL  SCHOOL  LIBRARY 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 


I  4- 


12 


000 


P 


OCT  2  0 
6  -  1941 


Uv     a  1941 

• 

KB  1  4  1943 

JUN  2  y  1943 
JUL 


J943 

SEP  *  -  1943 
AUG  ^  i  1344 


MAR  1  3  1948 


V  A 


U949 


2m-5,'31 


